Computer implemented method of determining a steering angle of a trailing bogie of a railway vehicle, bogie steering control unit for determining the steering angle and railway vehicle with the bogie steering control unit

Abstract

The present disclosure relates a method of determining a steering angle (20) of a trailing bogie (19), to a bogie steering control unit (10) and to a railway vehicle (12) comprising the bogie steering control unit (10). Specification data (21) of the railway vehicle (12) is provided, which comprises position information of a trailing bogie (19) and at least one leading bogie (17, 18) with respect to a chassis (13) of the railway vehicle (12). An angular position signal (22) is received, which is indicative of an angle between the rolling direction (X) of at least one wheel of the at least one leading bogie (17, 18) and a chassis portion (14) of the railway vehicle (12). Further, a distance signal (23) is also received, which is indicative of a distance (24) traveled by the railway vehicle (12). The steering angle (20) of the trailing bogie (19) is determined by using the specification data (21), the angular position sensor signal (22) and the distance signal (23).

Description

[0001] P28790PC00 September 2025

[0002] 1 / 47

[0003] COMPUTER IMPLEMENTED METHOD OF DETERMINING A STEERING ANGLE OF A TRAILING BOGIE OF A RAILWAY VEHICLE, BOGIE STEERING CONTROL UNIT FOR DETERMINING THE STEERING ANGLE AND RAILWAY VEHICLE WITH THE BOGIE STEERING CONTROL UNIT

[0004] FIELD OF THE DISCLOSURE

[0005] The present disclosure relates to a computer implemented method of determining a steering angle of a trailing bogie of a railway vehicle guided on a railway track, to a bogie steering control unit for determining a steering angle of a trailing bogie of a railway vehicle guided on a railway track and to a railway vehicle comprising the bogie steering control unit.

[0006] BACKGROUND OF THE DISCLOSURE

[0007] Railway vehicles, which are track bound such as trains, trams or other vehicles often exhibit wheels that are not optimally aligned to the tracks leading to higher friction between the railway track and treads of the wheels. Especially in curves with a small radius, this contact leads to an increased profile wear and noise pollution. In case of low-floor vehicles, this effect is even more pronounced: The low-floor vehicles feature smaller and less wheels per vehicle in order to increase the passenger comfort and inner space of the vehicle by having a continuous low-floor structure. However, this further leads to enhanced loads per wheel and a more pronounced fatigue of the wheel’s material causing smaller rifts or even larger material fractures.

[0008] Several attempts are known to reduce track and wheel wear. In the 1990’s, systems have been developed that were able to steer the wheels in curves. However, it turned P28790PC00 September 2025

[0009] 2 / 47 out that these solutions often suffered from undesired side effects in straight track sections such that the wheels adhered one-sided with the tread on the track, leading to an enhanced wear and noise in straight track sections. Hence, after a few years, most of these concepts were discarded and conventional concepts combined with wheel-noise absorbers and advanced industrial lubricants were again pursued.

[0010] One example of a railway bogie, which addresses these disadvantages in a successful manner is the WO2018015290 published 2018 in the name of the same applicant. The disclosed vehicle comprises a wheel assembly interconnected to a chassis as well as a method for steering said vehicle. The wheel assembly comprises a cross-member having a first end to which a first hub is interconnected by a first steering joint and a second end to which a second hub is interconnected by a second steering joint. A first wheel is attached to the first hub rotatable around a first rotation axis and a second wheel is attached to the second hub rotatable around a second rotation axis.

[0011] SUMMARY OF THE DISCLOSURE

[0012] It is an object of the present disclosure to provide a method for determining a steering angle of a bogie of a railway vehicle, to provide a bogie steering control unit configured to determine a steering angle and a railway vehicle comprising the bogie steering control unit. In particular, it is an object of the present disclosure to provide a method for determining a steering angle of a bogie of a railway vehicle, to provide a bogie steering control unit and railway vehicle comprising the bogie steering control unit, which address at least some of the disadvantages of the prior art.

[0013] According to the present disclosure, these objects are addressed by the features of the independent claims. In addition, further advantageous variations follow from the dependent claims and the description. P28790PC00 September 2025

[0014] 3 / 47

[0015] According to the present disclosure, a computer-implemented method of determining a steering angle of a trailing bogie of a railway vehicle guided on a railway track is specified. The railway vehicle comprises the trailing bogie and at least one leading bogie arranged, with respect to the direction of travel, in front of the trailing bogie. In other words, the railway vehicle comprises at least two bogies, which are configured to contact the railway track such that the railway vehicle is guided on the railway track. The travel direction is defined by the direction towards which the railway vehicle travels to. One of the bogies, the leading bogie, is arranged in front of the other bogie, the trailing bogie, during operation of the railway vehicle along the railway track in the direction of travel. If the direction of travel switches, the respective allocation would also switch.

[0016] The method comprises the step of providing specification data of the railway vehicle. The specification data is for example stored in a memory of a controller or a server and the method, in particular the respective device, which performs the method step may access the respective memory and retrieves the specification data. The specification data may also at least partially alternatively or additionally be sent or received as manual input from an operator. The specification data determines at least partially the railway vehicle, in particular its bogies. The specification data comprises in particular position information of the bogies with respect to a chassis of the railway vehicle. In other words, the specification data determines at which position of the chassis of the railway vehicle the different bogies, in particular the leading bogie and the trailing bogie, are arranged and connected to the chassis. The specification data thereby determines the distance between the different bogies, in particular its wheels, in the direction of travel.

[0017] The method further comprises the step of receiving an angular position signal, which is indicative of an angle between the rolling direction of at least one wheel of the at least one leading bogie and a chassis portion of the railway vehicle at which the respective leading bogie is connected. The rolling direction is defined by the direction towards which P28790PC00 September 2025

[0018] 4 / 47 the wheels roll during their operation. It is noted that a slip of the wheels may cause a difference between the direction of travel of the railway vehicle and the rolling direction. In a variation, the angular position signal may be indicative of an angle between a virtual plane stretched by the wheel circumference and the chassis portion. In other words, the angular position signal is indicative of the orientation of the wheel with respect to the chassis portion.

[0019] For example, in a straight segment of the railway track, the wheel and the respective chassis portion are arranged parallel or perpendicular with respect to each other. In a curve the orientation of wheel to the chassis portion needs to change such that the bogie and the railway vehicle follow the curved railway track and do not derail. The individual wheels of the bogie are therefore rotatable or swivelable arranged around a vertical axis at the chassis of the railway vehicle. The rotation of the wheels is caused by the design of the wheels in combination with the design of the railway tracks. The wheels may follow automatically the railway tracks during the operation of the railway vehicle, thereby rotating around the vertical axis with respect to the chassis of the railway vehicle. The rotation angle between the wheels of the railway bogie, in particular the rolling direction of the wheels, and the chassis portion at which the respective bogie is arranged, is measurable e.g. by an angle rate sensor, which provides the angular position signal.

[0020] The method further comprises the step of receiving a distance signal or travel signal, which is indicative of a distance traveled by the railway vehicle during its operation. The distance signal is for example the speed over time of the vehicle or a GPS position signal, which is constantly or at specific time intervals received. Important is that the distance signal enables to determine the traveled distance by the railway vehicle during its operation, in particular at any point in time. The distance signal may therefore also be a constantly received position signal, which enables to determine the traveled distance. With P28790PC00 September 2025

[0021] 5 / 47 the distance signal it is possible to determine when the trailing bogie passes a specific point or section of the railway track previously passed by the at least one leading bogie.

[0022] The method further comprises the step of determining the steering angle of the trailing bogie by using the specification data, the angular position sensor signal and the distance signal. The trailing bogie of the railway vehicle is for example actively steerable by an actuator, which is configured to slightly rotate or swivel the trailing bogie around a vertical extending axis with respect to the chassis of the railway vehicle. The method determines the steering angle of the trailing bogie such that the trailing bogie is advantageously steerable on the railway track, thereby reducing noise and wear of the trailing bogie. The specification data, in particular the position information of the bogies determines the required travel distance from the leading bogie to the trailing bogie. The angular position sensor of the leading bogie at a railway track point or section can be used to steer the trailing bogie, when it passes the same railway track point or section determined using the specification data and the distance signal. For example, the angle between the rolling direction of at least one wheel of the leading bogie and the chassis portion is received e.g. via respective sensors and respectively applied to the trailing bogie such that the trailing bogie, in particular the tread of at least one wheel of the trailing bogie, is similarly positioned on the respective track point or section as the respective tread of the leading bogie. The angular position signal in combination with the distance signal and the specification data advantageously enables to determine a steering angle for the trailing bogie, which is advantageously accurate and reliable. By using the determined steering angle, it is possible to reduce the noise and the wear of the trailing bogie during its operation because the trailing bogie, in particular the treads of its wheels are advantageously aligned during its operation. Further, by determining the steering angle constantly it is possible to steer the trailing bogie during the operation of the railway vehicle advantageously accurately. This solution is also applicable when only a portion of the bogies of P28790PC00 September 2025

[0023] 6 / 47 the railway vehicle is steerable. The steering angle may also be determined for a plurality of steerable trailing bogies.

[0024] A bogie is to be understood as pivoting bogie comprising elements such as H- or O- frames, wheelsets, axels, coil spring suspension and bearings, motors or drives. Furthermore, the bogie may comprise sensors such as for measuring distances, times, angles or rotation. Moreover, a railway vehicle may comprise a plurality of bogies, wherein at least one, a plurality or all of them are actively steerable e.g. via respective actuators. A bogie is not to be misunderstood with the term chassis as used in this patent application. A chassis is referred to as the frame of the railway vehicle, in particular of wagons of the railway vehicle.

[0025] Further increasing the accuracy of the determined steering angle is possible when the railway vehicle comprises a plurality of leading bogies each being arranged in front of the trailing bogie with respect to the direction of travel. The method further comprises to receive from the plurality of leading bogie the angular position signal and I or the distance signal. In other words, the plurality of leading bogies provides their angular position signal and I or their distance signal. The plurality of angular position signals and I or the plurality of received distance signal advantageously increase the accuracy of the determined steering angle.

[0026] It is preferred that the method step of receiving the angular position sensor comprises to receive from the plurality of leading bogies a respective angular position sensor signal, which is indicative of the angle between the rolling direction of the wheel of the respective leading bogie and the respective chassis portion of the railway vehicle at which the respective tread of the leading bogie is connected, and wherein the steering angle of the trailing bogie is determined by using the plurality of the received angular position signals. P28790PC00 September 2025

[0027] 7 / 47

[0028] The railway vehicle may comprise a plurality of different kind of bogies, which are arranged individually at the chassis of the railway vehicle. Receiving the respective distance signals and the angular position signals enables in view of the respective specification data to advantageously increase the accuracy of the determined steering angle of the trailing bogie, in particular because two or more signals are combined or one may be used for verification. The specification data comprises in this variation preferably the respective data of each relevant bogie.

[0029] It is further possible to increase the accuracy of the determined steering angle, when the specification data comprises information of the bogie type, the number of wheelsets per bogie, the geometrical extensions of the respective bogie, the position of the at least one wheelsets or wheels at the respective bogie and / or the degrees of freedom of rotation of the different wheels. The bogie type may determine if the entire bogie, if the wheelsets or if only the wheels are configured to be rotatable with respect to the chassis of the railway vehicle. The bogie type may further determine if the respective bogie is connected to only one wagon of the railway vehicle or to two, e.g. being arranged between two wagons of the railway vehicle. The number of wheelsets per bogie and the geometrical extensions of the respective bogie and the mentioned information is e.g. information used for interpreting the received angular position signal. Different specification data of different kinds of bogies or bogies arranged at different positions at the vehicle should be adapted I transferred such that the steering angle for the trailing bogie is useable. By taking into account at least one of the above-mentioned specification information it is possible to advantageously accurately determine the steering angle of the trailing bogie.

[0030] In a further variation, the method comprises the step of receiving from a lateral sensor of the leading bogie and / or the trailing bogie of the railway vehicle, a lateral sensor signal, which is indicative of a lateral position of at least one tread of the wheel of the respective P28790PC00 September 2025

[0031] 8 / 47 bogie with respect to the railway track. The steering angle of the trailing bogie is determined by further using the at least one lateral sensor signal. The lateral position of the tread with respect to the railway track determines which area of a rolling surface of the tread is during operation in contact with the railway track. Noise pollution is usually caused by the bogies of the railway vehicle during operation in case the lateral position of the tread with respect to the wheel is not as desired. For example, a flange of the tread may contact in a narrow curve the railway track, which causes the noise pollution and wear. The lateral position of the tread with respect to the rail may vary during the movement of the wheel along the rail either due to slightly varying track width or due to curvature of the track etc. The information of the current lateral distance between the tread of at least one wheel of the trailing bogie and I or of the leading bogie and the rail can advantageously increase the accuracy of the steering angle, such that during steering, the lateral distance of the tread of at least one wheel of the trailing bogie is kept constant or is adapted such that noise and or wear of the trailing bogie is reduced.

[0032] It is preferred that the received lateral sensor signal is used to determine the lateral distance of at least one tread of the trailing bogie and the respective rail of the railway track, and wherein the steering angle of the trailing bogie is determined such that the lateral distance is kept within a predetermined threshold band in particular at least when traveling along a predetermined railway track section. This variation ensures that the steering angle of the trailing bogie is determined such that the lateral distance is kept within the predetermined threshold band. The steering angle is thereby not only determined in dependence of signals from the leading bogie but also using the current relative position of the trailing bogie with respect to the railway track. Different lateral positions of the trailing bogie may therefore lead to slightly different determined steering angles.

[0033] It is further preferred that the threshold band is adapted in dependence of the railway track geometry or the speed of the railway vehicle. E.g. In narrow curves or in challenging P28790PC00 September 2025

[0034] 9 / 47 sections like crossings or switch points, the threshold band is increased. In straight segments or at higher speeds, the threshold band may be reduced.

[0035] In a further variation, the method further comprises the step of providing railway track geometry information, which are indicative of a curvature, an inclination, lateral distances between the rails of the railway track, track switch positions, track crossing positions of the railway track or geographical markers of the railway track. The track geometry information is e.g. measured, collected in advance and stored such that it is accessible by the device, which executes the described method step. The railway track geometry information may be provided I accessed in dependence of the current track section on which the railway vehicle is in operation. The track geometry information is further used to determine the steering angle of the trailing bogie, e.g. in that the track geometry information directly enters into the determination of the steering angle and I or in that this information is used as a verifying value for the determined steering angle. A combination of both would of course also be conceivable. The geographical markers are e.g. optical markers or electronic (RFID) markers on the railway track, which are detected by respective sensors e.g. cameras or RFID systems and which may be used to determine the position or position change, corresponding to the distance signal, of the railway vehicle.

[0036] It is preferred that the track geometry information is received as sensor signal, from at least one sensor of the railway vehicle. The railway vehicle may comprise at least one sensor, which is configured to provide a sensor signal, which is indicative of the track geometry information. The sensor signal may be indicative of the expected curvature etc. of the upcoming railway track section.

[0037] The track geometry information is advantageously providable, when the at least one sensor of the railway vehicle comprise an RFID-sensor, a LIDAR-sensor, a RADAR-sensor, cameras, a force sensor, a magnetic field sensor and / or a global position sensor, which P28790PC00 September 2025

[0038] 10 / 47 are configured to provide the sensor signal indicative of the track geometry information. The radio frequency identification sensor (RFID sensor) may be triggered, when the railway vehicle crosses a specific railway track section comprising a respective RFID sensor counterpart element. The provided RFID signal may indicate that the railway vehicle has reached or is passing a specific railway track section having e.g. a curvature of +2 degrees for 500 meters. The passing of the RFID sensor of the next RFID sensor counterpart may indicate that the former railway track section ends and that a following track section having a curvature of -1 degrees for 1000 meters follows. The light detection and ranging sensor (LIDAR-sensor) is a sensor for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. The LIDAR-sensor may be fixedly arranged at the railway vehicle and may be directed towards the railway track. Changes in the railway track, e.g. curvature, crossings or switches, may be detected by the LIDAR-sensor and are provided as the track geometry information. Similarly, the radio detection and ranging sensor (RADAR sensor) or the camera sensor may provide the respective track geometry information. The camera may provide images, which are analyzed for determining the track geometry information. The magnetic field sensor may be arranged at the railway vehicle and can provide track geometry information with regards to the railway vehicle, in that different railway track section may be identified by their individual magnetic field profile. Similarly, the GPS sensor may provide the respective track geometry information with regards to the railway vehicle. The force sensor may be arranged on a wheelset of the railway vehicle to measure lateral forces of the railway vehicle with respect to the railway track in that different railway track section may be identified by their individual lateral force profile. The track geometry information is valuable information for determining the steering angle either directly and I or as verification data. Further, the lateral forces may be used to validate the steering angle. E.g. in case the measured lateral forces exceed a predetermined threshold the steering angle may not lead to an optimal aligned tread on the railway track section. P28790PC00 September 2025

[0039] 11 / 47

[0040] It is further preferred when the received sensor signals from at least two of the sensors are combined with each other to determine the track geometry information. In this variation, at least two sensor signals from two sensors indicative of the track geometry information are combined or fused with each other (sensor fusion). By combining two or more sensor signals it is possible to receive an overview of the situation having less uncertainty compared when the different sensor sources would be used individually.

[0041] Further, the distance signal and I or the angular position signal may be determined by an estimation algorithm using the at least one of the received sensor signals. For example, during operation a sensor signal of the distance travelled of the trailing bogie or the leading bogies on the railway track is received and stored in a memory of a controller or a server. When the railway vehicle travels along the same railway track section again the sensor signal is received again and matched with the stored sensor signal in order to validate the newly received sensor signal. By using the former and the newly received sensor signal the accuracy may be increased. Further, the respective sensor signal may be stored and used respectively each time the railway vehicle passes the respective railway track section.

[0042] It is also preferred that the track geometry information is provided from a track geometry storage, which may comprise the respective information collected by a different railway vehicle, which previously traveled along the respective railway track section. In this variation, the track geometry information of a railway track is acquired i.e. by means of the at least one sensor of a different railway vehicle on the railway track.

[0043] It is further preferred that the track geometry information received as sensor signal is used in combination the track geometry information received from the track geometry storage. In this variation, the track geometry information received from the track geometry storage may be used to validate the track information received. P28790PC00 September 2025

[0044] 12 / 47

[0045] In a variation, the step of determining the steering angle of the trailing bogie comprises that the received angular position sensor signal is transformed into the steering angle for the trailing bogie in dependence of the specification data and the distance signal (and the other sensor signals) and further by using a transformation algorithm, wherein the transformation algorithm causes that the tread of at least one wheel of the trailing bogie, when being steered with the determined steering angle, is at least in specific railway track sections slightly differently aligned to the railway track compared to the tread of the leading bogie was at the same railway track section. If the treads of the trailing bogie would be aligned exactly as the treads of the leading bogie the wear and the noise caused by the leading bogie could also be caused by the trailing bogie. It is therefore advantageous if the trailing bogie is aligned slightly differently, e.g. further by using the measured lateral distance. The leading bogie is e.g. caused to turn by a contact of one of its wheel flanges with the rail. This contact may cause noise and wear, which should be avoided. The transformation algorithm may use all of the available information to transform the received angular position sensor signal such that the respective flange of the wheel of the trailing bogie is, by the determined steering angle, steerable such that it does not contact the rail at the same track section, thereby reducing the noise and I or the wear. At the same time the transformation algorithm may ensure that the trailing bogie is not steered by the determined steering angle such that it may harm or damages the trailing bogie, the rail or the entire vehicle.

[0046] In a further variation, the method comprises the steps of assigning the determined steering angle of the trailing bogie to a railway track section and to determine the steering angle of the trailing bogie by further using the assigned steering angle when the railway vehicle passes the railway track section again. Railway vehicles, in particular trams or underfloor trains, run on local railway networks throughout their operating timespan for the respective operator. They travel along the same routes or portions of the railway network many times or even all the time. In other words, it is not unusual for railway P28790PC00 September 2025

[0047] 13 / 47 vehicles to travel from A to B and back or in circles for many times within a day or within weeks or months. The steering of the trailing bogie should be always the same when running along the same railway track section such that entire railway vehicle is guided always as accurately as possible. By assigning the determined steering angle to at least one railway track section or by assigning the determined steering angle to the entire railway track section it is possible to reuse the determined steering angle many times. The railway vehicle may comprise a GPS sensor or other positioning sensors, which are configured to determine the exact position of the vehicle with respect to the rail such that the assigned steering angle can be used to determine the steering angle of the trailing bogie when the railway vehicle passes the railway track section again. According to this variation it is possible to further advantageously increase the accuracy of the determined steering angle. The assigned steering angle may also be updated, in particular constantly updated, by the newly determined steering angle.

[0048] It is a further variation of the method to further comprise a step of determining a steering angle of the at least one leading bogie by using the determined steering angle of the trailing bogie and / or the at least one leading bogie. All bogies of the railway vehicle are for example actively steerable e.g. by an actuator. Each actuator may be configured to slightly rotate or swivel all bogies independently from each other around a vertical extending axis of each bogie with respect to the chassis of the railway vehicle. In this variant, the at least one leading bogie operates similarly as the trailing bogie and / or leading bogie. In this variation the steering angle of the trailing bogie and the at least one leading bogie may be determined in combination such that all bogies are advantageously steerable on the railway track. In another variant, the steering angle of the at least on least one leading may be determined in combination of a determined steering angle of the at least one leading bogie from a previous operation, in particular a previous operation on a railway track and a steering angle the at least one leading bogie during operation on the same railway track. P28790PC00 September 2025

[0049] 14 / 47

[0050] In a further variation, the method comprises the steps of assigning the determined steering angle of the leading bogie to a railway track section and to determine the steering angle of the leading bogie by further using the assigned steering angle when the railway vehicle passes the railway track section again. Also, the steering of the leading bogies, if possible, should be always the same when running along the same railway track section such that entire railway vehicle is guided always as accurately as possible. By assigning the determined steering angle to at least one railway track section or by assigning the determined steering angle to the entire railway track section it is possible to reuse the determined steering angle many times. For example, the first time the railway vehicle, comprising the steerable at least one leading bogie, passes a respective railway track section, the at least one leading bogie is not steered. The determined steering angle is assigned and stored. The subsequent times the same railway vehicle passes the respective railway track section, the at least one leading bogie is steered using the assigned steering angle. Sensor data may further be used to update the steering angle and I or to validate the steering of the leading and I or trailing bogie. According to this variation it is possible to further advantageously increase the accuracy of the determined steering angle of the at least one leading bogie. The assigned steering angle may also be updated, in particular constantly updated, by newly determined steering angle of the least one leading bogie.

[0051] In a variation, the method further comprises the step of providing a trained neural network, which is trained by the received sensor signals and by the resulting steering angle at a specific railway track section, and wherein the steering angle of the trailing bogie is determined by further using the trained neural network, wherein at least the received angular position signal and the distance signal are used as input data for the neural network and the steering angle is the output of the neural network. The trained neural network provides the advantage that the received plurality of sensors signals can be P28790PC00 September 2025

[0052] 15 / 47 advantageously provided as input data to the trained neural network and the neural network determines the steering angle.

[0053] In a further variation, the method comprises the step of steering the trailing bogie on the railway track by using the determined steering angle. The determined steering angle is e.g. transferred to a control command for a steering actuator, which is connected to the chassis of the railway vehicle and the trailing bogie and which is configured to swivel or rotate the trailing bogie around a vertical steering axis, thereby guiding or steering the trailing bogie on the railway track. The steering actuator is controlled by using the determined steering angle.

[0054] According to a further aspect of the present disclosure a bogie steering control unit is specified. The bogie steering control unit is configured to determine a steering angle of a trailing bogie of a railway vehicle guided on a railway track. The railway vehicle comprises the trailing bogie and at least one leading bogie arranged in front of the trailing bogie with respect to the direction of travel, wherein the bogie steering control unit comprises a processor or electric circuit.

[0055] The processor or electric circuit of the bogie steering control unit is further configured to access or receive specification data of the railway vehicle, wherein the specification data comprises position information of the bogies with respect to a chassis of the railway vehicle. The specification data is for example stored in a memory of the bogie steering control unit or a server and the processor or the electric circuit accesses the respective memory and retrieves or the required specification data. In other words, the specification data determines at which position of the chassis of the railway vehicle the different bogies, in particular the leading bogie and the trailing bogie, are arranged and connected to the chassis. The specification data thereby determines the distance between the different bogies, in particular its wheels. P28790PC00 September 2025

[0056] 16 / 47

[0057] The processor or electric circuit of the bogie steering control unit is configured to receive an angular position signal, which is indicative of an angle between the rolling direction of at least one wheel of the at least one leading bogie and a chassis portion of the railway vehicle at which the respective leading bogie is connected.

[0058] The processor or electric circuit of the bogie steering control unit is further configured to receive a distance signal, which is indicative of a distance traveled by the railway vehicle during its operation.

[0059] The processor or electric circuit of the bogie steering control unit is further configured to determine the steering angle of the trailing bogie by using the specification data, the angular position signal and the distance signal.

[0060] It is preferred that the bogie steering control unit is configured to execute any method step as described above and hereinafter.

[0061] The bogie steering control unit may be implemented as a single control unit or a plurality of interconnected control units, which may be arranged at least partially remotely from the railway vehicle.

[0062] All of the features, details and advantages introduced and described above and hereinafter with respect to the method of determining the steering angle for the trailing bogie may apply or may be used to limit the aspect of the bogie steering control unit which is configured to determine the steering angle for the trailing bogie mutatis mutandis.

[0063] According to a further aspect of the present disclosure, a railway vehicle is specified. The railway vehicle comprises a trailing bogie and at least one leading bogie arranged in front of the trailing bogie with respect to the direction of travel. The railway vehicle may P28790PC00 September 2025

[0064] 17 / 47 further comprise a bogie steering control unit, which is configured to determine the steering angle of the trailing bogie. The bogie steering control unit or at least a portion of it may also be implemented remotely from the railway vehicle. The railway vehicle further comprises an actuator, e.g. a hydraulic cylinder, which is configured to steer the trailing bogie with respect to a chassis of the railway vehicle by using the determined steering angle. The actuator is e.g. connected at one side with the chassis and at the other side with the trailing bogie, such that a movement of the actuator causes the trailing bogie to swivel around a vertically arranged steering axis. The determined steering angel is e.g. transferred to a control signal for the actuator for steering of the trailing bogie respectively. Other steering actuators or devices are of course also conceivable.

[0065] According to a further aspect of the present disclosure, a computer-implemented method for determining a geographical position of a railway vehicle guided on a railway track is specified. The railway vehicle comprises in particular at least one inductive sensor, which is configured to provide an inductive sensor signal. The method may comprise the following steps:

[0066] In a first step an inductive sensor signal is received during the operation of the railway vehicle on the railway track, wherein the inductive sensor signal is indicative of at least one metal infrastructure object in vicinity of the railway track just passed. The inductive sensor is, e.g. directed towards the railway track, and measures, in particular continuously, during the operation of the railway vehicle. The at least one inductive sensor is e.g. arranged on the railway vehicle above one of the railway tracks or in a center area between the two railway tracks. The specific position of the inductive sensor is not critical, important is that the at least one inductive sensor is arranged and configured to provide the meaningful inductive sensor signal. The railway vehicle, e.g. a train, tram or streetcar, passes over junctions, manholes etc., which cause a deflection in the inductive sensor signal. The deflection may also be described as a change or something readable of the P28790PC00 September 2025

[0067] 18 / 47 measured inductive sensor signal. In other words, a change in the magnetic field generated by the inductive sensors caused by the at least one metal infrastructure object in the vicinity of the railway track is measured by the at least one inductive sensor, when the railway vehicle passes over the respective metal infrastructure object.

[0068] In a further step, reference signals are provided, which are stored in a database, wherein the reference signals are linked to a specific geographical location of the railway track of the respective reference signals. The reference signals are e.g. provided in a database located at the railway vehicle accessible by a processor, which executes the computer implemented method. In another embodiment, the database storing the reference signals is located in a remote location e.g. a cloud server, which is accessible by the respective processor for performing the required steps. The reference signals are further linked to a specific geographical location of the railway track, e.g. its exact global positioning coordinates (GPS), track number, distance from last bifurcation etc..

[0069] In a further step, the current geographical position of the railway vehicle on the railway track is determined, by comparing the received inductive sensor signal with the reference signals. The received inductive sensor signal is, e.g. continuously or section wise, compared to the stored reference signals. In other words, the method tries to match the received inductive sensor signal to the stored reference signals. In case the received inductive sensor matches to a specific reference signal, the current geographical position of the railway vehicle can be determined from the linked geographical position of the matched reference signal. For example, a comparison algorithm is used to match the received inductive sensor signal with the stored reference signals. The determined current geographical position is an unique information or data to identify the position of the railway vehicle on the railway network. This could be the exact global position coordinates, the track number, the distance from the last reference mark, like a bifurcation etc. P28790PC00 September 2025

[0070] 19 / 47

[0071] This depends on the respective linked geographical information of the matched reference signal.

[0072] The above and hereinafter described steps are preferably performed by a position estimator, which is an algorithm running on a processor or control unit of the railway vehicle or remotely of the railway vehicle.

[0073] According to this aspect of the present disclosure it is possible to determine the geographical position of the railway vehicle running on the railway track during its operation, by using a simple and reliable sensor signal and the already present infrastructure in the vicinity of the railway tracks. In particular in tram or streetcar applications running in city centers many different metal objects are present near the railway track, which makes it especially easy and reliable to determine the position of the railway vehicle.

[0074] This aspect of the present disclosure, namely to determine the current geographical position may be alone or in connection with other aspects or embodiments of the present disclosure subject of one or more divisional applications and I or may form the priority founding application of any subsequent patent application directed to this aspect.

[0075] According to an embodiment of this aspect, the determined current geographical position of the railway vehicle is further used to determine the steering angle of the trailing bogie as described above and hereinafter with respect to the computer-implemented method of determining a steering angle of a trailing bogie of a railway vehicle guided on a railway track. In other words, the determined geographical position of the railway vehicle is in addition to the specification data, the angular position sensor signal and the distance signal used to determine the steering angle of the trailing bogie. The determined geographical position may be used as an alternative to the distance signal or may be used to increase the accuracy of the distance signal. P28790PC00 September 2025

[0076] 20 / 47

[0077] According to an embodiment of this aspect, the reference signals are recorded by at least one respective reference run along the railway track using an inductive sensor and a position measurement device. A plurality of reference runs with a respective vehicle may be used to increase the accuracy of the reference signals. The position measurement device provides an accurate and precise source of position information. The position measurement device is e.g. temporarily installed in the railway vehicle for the reference measurement. In other words, the position measurement device determines the respective position coordinates of the railway vehicle, which can be linked to the measured reference signals. The position measurement device uses for example, speed-over- ground radar sensors, wheel encoders, in particular specific well calibrated wheel encoders, or other systems to determine the respective position coordinates of the metal infrastructure objects. The position measurement device provides in particular a more accurate position measurement compared to a standard GPS system.

[0078] Furthermore, the references signals may be continuously updated by using the received inductive sensor signal. Thereby improving the accuracy overtime and enabling to detect changes of the metal infrastructure of the railway tracks over time.

[0079] According to an embodiment of this aspect, the metal infrastructure object in the vicinity of the railway track, which is measured by the inductive sensors, comprises railway track infrastructure, metal covers on the ground, manholes and / or specific metal objects. The railway track infrastructure includes the rails, rail junctions, rail crossings, varying rail geometry and any other kind of measurable rail infrastructure. Specific metal objects are e.g. specifically places in order to increase the metal infrastructure in areas without any specific kind of conventional metal infrastructure to increase the accuracy of the measur- ment. P28790PC00 September 2025

[0080] 21 / 47

[0081] According to a further embodiment of this aspect, the method additionally comprises the step of receiving the distance signal, which is indicative of a distance traveled by the railway vehicle during its operation as described above and hereinafter with respect to the computer-implemented method of determining a steering angle of a trailing bogie of a railway vehicle guided on a railway track. The distance signal is additionally used for determining the current geographical position of the railway vehicle on the railway track, in particular between at least two deflections in the inductive sensor signal. It is thereby also possible to determine the geographical position of the railway vehicle between at least two reference signal positions.

[0082] According to a further embodiment of this aspect, the method additionally comprises the step of receiving a gps signal, which is indicative of the gps coordinates of the railway vehicle during its operation. The gps signal is e.g. additionally used for determining the current geographical position of the railway vehicle on the railway track, in particular between at least two deflections in the inductive sensor signal. It is thereby also possible to determine the geographical position of the railway vehicle between at least two reference signal positions.

[0083] According to a further embodiment of this aspect, the inductive sensor signal, which is compared to the reference signals comprises a deflection sequence, comprising in particular one or more deflections, wherein each deflection corresponds to at least one of the metal infrastructure objects, and wherein the reference signals also comprises a respective deflection sequence.

[0084] According to a further embodiment of this aspect, a plurality of deflections forms the inductive sensor signal, which is compared to the respective reference signals. Such a deflection sequence may comprise at least two or more deflections. In another embodiment, each deflection sequence corresponds to the measured inductive sensor signal P28790PC00 September 2025

[0085] 22 / 47 over time, e.g. 5 or 10 seconds, or distance traveled e.g. 100 m or 250 m. Furthermore, the deflection sequences are automatically or manually fitted.

[0086] According to a further embodiment of this aspect, specific parameters of the measured inductive sensor signal, like height of the deflection, upside gradient, downside gradient, peak length etc. are identified and compared to respective specific parameters of the reference signals.

[0087] According to a further embodiment of this aspect, a pattern of the measured inductive sensor signal, comprising e.g. a plurality of deflections, with specific properties, is identified and compared to respective specific patterns of the reference signals. The deflection patterns forming the reference signal automatically or manually fitted.

[0088] According to a further embodiment of this aspect, the method, in particular the position estimator uses a SLAM algorithm for determining the current geographical position of the railway vehicle, wherein at least the measured inductive sensor signal is used as input data. The received distance signal and the reference signal may also be used additionally as input data.

[0089] According to a further embodiment of this aspect, the railway vehicle is equipped with a plurality of inductive sensors, wherein each provide a respective inductive sensor signal. For example, one inductive sensor is directed from the railway vehicle downwards towards one railway track and a second inductive sensor is directed from the railway vehicle downwards towards the second railway track. In another embodiment, one or more inductive sensors are arranged in the center area of the railway vehicle and are directed towards the area between the railway tracks. The plurality of sensors further improves the accuracy of the determination of the geographical position. P28790PC00 September 2025

[0090] 23 / 47

[0091] According to a further embodiment of this aspect, the reference signals form a reference map of the entire railway network of the railway tracks on which the railway vehicle is operating, thereby enabling to determine the current position of the railway vehicle of the entire railway network. The reference map is e.g. an entire city network or country network of railway tracks.

[0092] According to a further embodiment of this aspect, the method further comprises the step of preselecting the reference signals for comparing with the expected inductive sensor signal based on at least one previous determination of the geographical position of the railway vehicle on the railway track. For example, the previous matched reference signal was a reference signal prior of a junction of the railway track. In this case the two subsequently following reference signals are preselected and afterwords compared with the next received inductive sensor signal, which should match to one of the two preselected reference signals. In case the received measured inductive sensor signal does not match with one of the preselected reference signals it may be compared to the rest of the reference signals. According to this embodiment, the velocity of determining the current geographical position of the railway vehicle is advantageously increased.

[0093] It is to be understood that both the foregoing general description and the following detailed description present variations, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various variations, and together with the description serve to explain the principles and operation of the concepts disclosed. P28790PC00 September 2025

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[0095] BRIEF DESCRIPTION OF THE DRAWINGS

[0096] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing: Fig. 1 a first schematic view of a railway vehicle comprising a steerable bogie and a bogie steering control unit;

[0097] Fig. 2 a second schematic view of the railway vehicle of figure 1 further showing additional sensor signal input to the bogie steering control unit;

[0098] Fig. 3 a schematic view of an architecture of the bogie steering control unit; Fig. 4 a first perspective view of the steerable bogie;

[0099] Fig. 5 a second perspective view of the steerable bogie of figure 4, showing in particular the underside of the steerable bogie;

[0100] Fig. 6 a detail A of the underside of the steerable bogie indicated in Figure 5;

[0101] Fig. 7 a flow diagram indicating different steps of a method of determining a steer- ing angle for the trailing bogie;

[0102] Fig. 8 a schematic diagram representing the method of determining the current geographical position of the railway vehicle according to a further aspect of the present disclosure; P28790PC00 September 2025

[0103] 25 / 47

[0104] Fig. 9 a railway vehicle on railway tracks, metal infrastructure object in the vicinity of the railway tracks and inductive sensor signal of the metal infrastructure object according to this aspect:

[0105] Fig. 10 a flow diagram indicating different steps of the method of determining the current geographical position of the railway vehicle.

[0106] DETAILED DESCRIPTION OF THE DRAWINGS

[0107] Reference will now be made in detail to certain variations, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, variations disclosed herein may be embodied in many different forms and should not be construed as limited to the variations set forth herein; rather, these variations are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0108] Figure 1 shows a first schematic view of a railway vehicle 12 comprising a steerable bogie 1 and a bogie steering control unit 10. Figure 2 shows a second schematic view of the railway vehicle 12 of figure 1 further showing additional sensor signal input to the bogie steering control unit 10. Figure 3 shows a schematic view of an architecture of the bogie steering control unit 10. Figure 4 shows a first perspective view of the steerable bogie 1 . Figure 5 shows a second perspective view of the steerable bogie 1 of figure 4, showing in particular the underside of the steerable bogie 1 . Figure 6 shows a detail A of the underside of the steerable bogie 1 indicated in Figure 5 and Figure 7 shows a flow diagram indicating different steps of a method of determining a steering angle 20 for a trailing bogie 19. P28790PC00 September 2025

[0109] 26 / 47

[0110] Figure 1 shows a railway vehicle 12, e.g. a railway street car or a tram, which operates on a railway track 15. The railway vehicle 12 is connected to and guided by bogies 17, 18, 19 on the railway track 15. In the shown variation, the railway vehicle 12 comprises three bogies, a first leading bogie 17 arranged in front of the railway vehicle 12, with respect to a rolling direction X, a second leading bogie 18 and a trailing bogie 19 arranged in the rear of the railway vehicle 12. The second leading bogie 18 or first trailing bogie 18, is arranged between the first leading bogie 17 and the trailing bogie 19. The railway vehicle 12 further comprises a chassis 13, which forms the frame of the different wagons of the railway vehicle 12, and which provides the connection possibilities to connect the bogies to the railway vehicle 12, in particular its wagons. The railway vehicle 12 as shown in Figure 1 comprises two wagons or sections, which are connected with each other. Figure 1 further shows that the different bogies 17, 18 and 19 have different specifications. The first leading bogie 17 and the second leading bogie 18 comprise two wheelsets, thereby having in sum four wheels 5, and the trailing bogie 19 only one wheelset thereby having in sum two wheels 5. Further, the first leading bogie 17 and the trailing bogie 19 are arranged only at one wagon of the railway vehicle 12. The second leading bogie 18 is arranged between the first and second wagon of the railway vehicle 12. The front portion of the second leading bogie 18 is e.g. connected to the front wagon and the rear portion of the second leading bogie 18 is e.g. connected to the rear wagon. A swiveling movement between the front wagon and the rear wagon due to a curvature of the railway track 15 may cause the second leading bogie 18 to swivel with respect to the front wagon and the rear wagon. Further, a curvature of the railway track 15 also causes the first leading bogie 17 to swivel with respect to the front wagon, in particular its chassis 13 of the railway vehicle 12 during the operation of the railway vehicle 12 on the railway track 15. The trailing bogie 19 is actively steerable. The two leading bogies 17, 18 are passively steered. In other words, the trailing bogie 19 is e.g. via a steering actuator 9 (shown in Figure 4) swivelable or rotatable around a steering axis 4 with respect to the chassis 13 of the railway vehicle 12. Further bogies could of course also be arranged P28790PC00 September 2025

[0111] 27 / 47 steerable on the railway vehicle. Figure 1 further advantageously shows that the different types of bogies 17, 18, 19 and the different positions of the bogies 17, 18, 19 with respect to the chassis 13 of the railway vehicle 13 cause different rotations of the bogies at different point in times when the railway vehicle 13 travels along the railway track 15 during its operation. Actively steered may be determined in that the rolling direction X of at least one wheel 5 of the trailing bogie 19 is amendable by an actuator system. Passively steered may be determined in that the rolling direction X of at least one wheel 5 of the leading bogie 17, 18 is amended by the railway track 15 when the bogie 17, 18 moves along the railway track 15.

[0112] Figure 1 further indicates a bogie steering control unit 10, which is configured to determine a steering angle 20 for the trailing bogie 19, in particular by a processor or an electric circuit 32. The bogie steering control unit 10 may be a single control unit which only provides the respective functionality. In another variation, the bogie steering control unit 10 may be included in another control unit for the railway vehicle 12 also providing the respective functionality. The bogie steering control unit 10 is configured to receive a plurality of sensor signals and is further configured to access or receive data e.g. stored in a memory base. The bogie steering control unit 10 is in particular configured to access or receive specification data 21 of the railway vehicle 12. The specification data 21 comprises position information of the bogies 17, 18, 19 with respect to the chassis 13 of the railway vehicle 12. Further, the specification data 21 may comprise information of the bogie type, the number of wheelsets per bogie, the position of the at least one wheelsets or wheels at the respective bogie and / or the degrees of freedom of rotation of the different wheels. The specification data 21 may be determined in that it includes all non-meas- ured information of the respective railway vehicle 12 for determining the steering angle 20. The bogie steering control unit 12 is further configured to receive an angular position signal 22, which is indicative of an angle between at least one rolling direction of the wheel 5 of the first leading bogie 17 and a chassis portion 14 at which the leading bogie P28790PC00 September 2025

[0113] 28 / 47

[0114] 17 is connected to the chassis 13. Figure 1 further indicates that also the second leading bogie 18 may transmit its angular position signal 22 to the bogie steering control unit 10. Further, it is visible that the first and second leading bogie 17, 18 also transmit a distance signal 23 to the bogie steering control unit 10. Further also the trailing bogie 19 transmits the distance signal 23 to the bogie steering control unit 10. The distance signal 23 is indicative of the distance traveled on the railway track 15 by the railway vehicle 10 during its operation, in particular during a specific timespan. Having a plurality of distance signals 23 increases the accuracy. The first leading bogie 17 and the second leading bogie

[0115] 18 may comprise an angular position sensor 29 and a distance signal sensor 30. The angular position sensor 29 is configured to measure and provide the angular position signal 22 to the bogie steering control unit 10 and the distance signal sensor 30 is configured to measure and provide the distance signal 23 to the bogie steering control unit 10. Further, also the trailing bogie 19 may comprise a respective distance signal sensor 30. The angular position sensor 29 may be an opto-electrical sensor or may be a magnetic sensor. Further, the angular position sensor 29 may be a distance sensor, which provides a signal transferrable to the angular position signal 22. The distance signal sensor 30 may be a GPS sensor, a sensor counting the revolutions of the respective wheel 5 of the bogies 17, 18, 19 within a given timespan, or an acceleration sensor or any other sensor capable of providing a signal indicative of the velocity over time or the distance traveled.

[0116] Figure 1 further indicate that the bogie steering control unit 10 is configured to determine the steering angle 20, in particular a respective signal, for steering the trailing bogie 19 using the specification data 21 , the received angular position signals 22 and the received distance signals 23. The determined steering angle 20 is applied as respective control signal to the trailing bogie 19, in particular to an actuator, such that the respective trailing bogie 19 is steered respectively during its operation. P28790PC00 September 2025

[0117] 29 / 47

[0118] In a variation, the leading bogies 17, 18 may also be steerable. In this case, the determined steering angle 20 of the trailing bogie 19 may be used to determine the steering angle 20 for the at least one steerable leading bogie 17, 18. This may be in particular used when the railway vehicle 12 travels many times over the same railway track sections 16.

[0119] Figure 2 shows a second variation of the railway vehicle 12 and the bogie steering control unit 10. The railway vehicle 12 differs from the variation as shown in Figure 1 in that it comprises additional track geometry sensors 27, which are arranged at the railway vehicle 12 and which are configured to provide track geometry information 26 to the bogie steering control unit 10. The track geometry information is e.g. indicative of a curvature, an inclination, lateral distances between the rails of the railway track 15, track switch positions and I or track crossing positions of the railway track 15. The track geometry sensor 27 may include an RFID-sensor, a LIDAR-sensor, a RADAR-sensor or at least one camera. The track geometry sensor 27 is preferably arranged at a front portion of the railway vehicle 12 and is directed towards the railway track 15 for capturing the above mentioned specifications of the railway track 15. The track geometry information 26 may also be used to determine the steering angle 20 for the trailing bogie 19. Figure 2 further shows a trained neural network 27, which may be accessed or used by the bogie steering control unit 10 for determining the steering angle 20 for the trailing bogie 19. Figure 2 further indicates a distance traveled 24 on the railway track 15 by the railway vehicle 12, in particular within a specific timespan.

[0120] Figure 3 shows the system architecture of the system for determining the steering angle 20 and to apply the determined steering angle 20 to the trailing bogie 19. Figure 3 may be divided into three portions, an upper portion above the upper dashed line, a lower portion below the lower dashed line, and a middle portion in between. The upper portion represents the sensors of the system and its measured sensor signals or data, which is P28790PC00 September 2025

[0121] 30 / 47 provided to the bogie steering control unit 10 as input data. The sensor signals in particular include the angular position signals 22, the distance signals 23, the lateral sensor signal 25 and the measured or sensed track geometry information 26. The middle portion represents the bogie steering control unit 10 and its features and non-measured input. The bogie steering control unit 10 access or receives the specification data 21 of the respective railway vehicle 12, which is also used to determine the steering angle 20. Further, other features like the trained neural network 28 or parts of the bogie steering control unit 10 may be allocated in the middle section. The lower portion represents the trailing bogie 19, which receives from the bogie steering control unit 10 the determined steering angle 20 as control command input. The trailing bogie 19 is steered on the railway track 15 by using the received steering angle 20. For example, the steering actuator 9 (shown in Figure 4) is controlled respectively.

[0122] Figure 4, 5 and 6 shows a variation of a steerable bogie 1 as it could be used in a tram. The bogie 1 comprises a base 2, which is configured to be rigidly attached to the chassis 13 of the railway vehicle 12. The bogie 1 further comprises a frame 3 arranged rotatable with respect to the base 2 around a vertical steering axis 4. The bogie 1 further comprises two wheels 5, which comprise each a tread 6. The tread 6 or tread profile is the radially external portion of the wheel 5. The tread 6 comprises a contact surface or a rolling surface, which is, during operation, in contact with the railway track 15. The wheels 5 are arranged rotatable with respect to the frame 3 around a respective wheel rotation axis 7. The wheel rotation axis 7 of the wheels 5 are arranged essentially coaxially to each other and the steering axis 4 is arranged in a lateral direction Y between the two wheels 5. In another variation, the wheel rotation axis 7 may be arranged at a specific angle with respect to the lateral direction Y. In this case, the wheel rotation axis 7 are inclined with respect to the lateral direction Y. Figure 4 further shows covers arranged on the frame 3 for protection of the bogie 1 during operation. Figure 5 does not show these covers. P28790PC00 September 2025

[0123] 31 / 47

[0124] The bogie 1 further comprises a lateral sensor 8, best visible in Figures 5 and 6, which is configured to determine during operation the lateral position of the tread 6 of at least one of the wheels 5 with respect to the railway track 15. The lateral sensor or plurality of lateral sensor 8 enable to determine the position of the treads 6 of the wheels 5 on the railway track 15 during operation, which is crucial to control the position of the treads 6 of the wheels 5 with respect to the railway track 15 for noise and wear control.

[0125] Figure 4 further shows a steering actuator 9, which is connected to the base 2, rigidly connectable to the chassis 13 of the railway vehicle 12. Movement of the steering actuator 9 cause a rotation of the frame 3 around the steering axis 4 by the steering angle 20 with respect to the base 2 and with respect the chassis 13 of the railway vehicle 12.

[0126] Figures 5 and 6 further show the lateral sensors 8 in detail. The lateral sensors 8 comprises a front sensor arranged in front of the respective tread 6 of the wheel 5 with respect to a rolling direction X of the bogie 1. The lateral sensors 8 further comprises a back sensor arranged behind the respective tread 6 of the wheel 5 with respect to the rolling direction X of the bogie 1. As best visible in Figure 5, both wheels 5 of the bogie 1 comprise the front sensor and the back sensor. The front sensors and the back sensors are arranged on a sensor bracket, which is mounted pivotable on the bogie 1. The sensor bracket extends along the wheel 5 and holds the respective sensors at a predefined position during operation of the bogie 1.

[0127] The Figures 4 to 6 further show that each wheel 5 comprises an electrical engine and a brake. The electrical engine is configured to drive, if required, during operation the respective wheel 5, and the brake is configured to decelerate, if required, during operation of the bogie 1 the respective wheel 5. The brake is preferably a disk brake and the disk of the disk brake is arranged on the same shaft as the respective wheel 5 and the respective electrical engine. The bogie 1 may further comprise a distance signal sensor P28790PC00 September 2025

[0128] 32 / 47

[0129] 30, which is configured to determine the distance traveled by the bogie 1 on the railway track 15. The distance signal sensor 30 may be a counter counting the revolutions of a wheel 5 or may be a GPS sensor etc.

[0130] Figure 7 shows a flow diagram illustrating a sequence of steps for determining the steering angle 20 for steering the steerable trailing bogie 19 as shown e.g. in the figures 4 to 6 of the railway vehicle 10 as shown e.g. in the figures 1 to 2. In the following paragraphs, described with reference to Figures 1 to 6 is a possible sequence of steps, performed by the bogie steering control unit 10 for determining the steering angle 20 and for steering the steerable trailing bogie 19 using the determined steering angle 20.

[0131] In step S1 , the bogie steering control unit 10 receives or accesses or uses the specification data 21 of the railway vehicle 12. The specification data 21 comprises position information of the bogies 17, 18, 19 with respect to the chassis 13 of the railway vehicle 12. The specification data 21 may further comprise additional important non-measured information of the railway vehicle 12, which might be important for determining the steering angle 20. The specification data 21 might be stored in a memory of the bogie steering control unit 10 or might be accessed remotely.

[0132] In step S2, the bogie steering control unit 10 receives the angular position signal 22 of at least one of the leading bogies 17, 18, which is indicative of the angle between the rolling direction X of at least one wheel 5 of the leading bogie 17, 18 and the chassis portion 14 of the railway vehicle 12 at which the respective leading bogie 17, 18 is connected to. A curvature of the railway track might cause the leading bogie 17, 18 to passively rotate with respect to the chassis portion 14, which is measured by the angular position sensor 30 and provided as angular position signal 22 to the bogie steering control unit 10. P28790PC00 September 2025

[0133] 33 / 47

[0134] In step S3, the bogie steering control unit 10 receives the distance signal 23 of at least one of the leading bogies 17, 18 and I or the trailing bogie 19, which is indicative of a distance 24 traveled by the railway vehicle 12 during its operation. The distance signal 23 provides information when the received angular position signal 22 of the leading bogies 17, 18 should be applied, applied respectively transferred, to the trailing bogie 19.

[0135] In step S4, the bogie steering control unit 10 may further receives the lateral sensor signal 25 from the lateral sensor 8 of the trailing bogie 19 and I or also of the leading bogies 17, 18. The lateral sensor signal 25 is indicative of a lateral position of at least one tread 6 of the respective bogie 17, 18, 19 with respect to the railway track 15.

[0136] In step S5, the bogie steering control unit 10 may further receives or accesses track geometry information 26, which is either measured by the track geometry sensor 27 or retrieved from a database. A combination would be of course also conceivable. The track geometry information 26 is indicative of at least one of: a curvature, an inclination, lateral distances between the rails of the railway track 15, track switch positions or track crossing positions of the railway track 15. The track geometry sensor 27 may comprise a RFID-sensor, a LIDAR-sensor, a RADAR-sensor or a camera.

[0137] In step S6, the bogie steering control unit 10 may further accesses or uses a trained neural network 28, which is trained by the received sensor signals 22, 23, 25, 26 and by the resulting steering angle 22 at a specific railway track section 16. It is preferred that the steering angle 22 of the trailing bogie 19 is determined by further using the trained neural network 28, wherein at least the received angular position signal 22 and the distance signal 23 are used as input data for the neural network 28 and the steering angle 20 is the output of the neural network 28. P28790PC00 September 2025

[0138] 34 / 47

[0139] In step S7, the bogie steering control unit 10, determines the steering angle 20 by using the specification data 21 and the received or retrieved sensor signals, in particular the angular position sensor signal 22, the distance signals 23, the lateral sensor signal 25 and the track geometry information 26.

[0140] In step S8, the bogie steering control unit 10, may assign the determined steering angle 20 to a specific railway track section 16. This is e.g. stored in respective memory or database accessible by the bogie steering control unit 10.

[0141] In step S9, the bogie steering control unit 10 may determine the steering angle 20 by further using the retrieved assigned steering angle 20 of the respective railway track section 16, when the railway vehicle 10 is expected to travel again along the respective railway track section 16.

[0142] Figure 8 shows a schematic diagram representing the method of determining the current geographical position 37 of the railway vehicle 12. Figure 8 shows a position estimator 41 , e.g. implemented as processor or electric circuit on the railway vehicle 12 or remote, wherein the position estimator 41 , is configured to perform the method for determining the current geographical position 37 of the railway vehicle 12 on the railway track 15. The position estimator 41 receives as input data an inductive sensor signal 33 from at least one inductive sensor 38, shown in Figure 9, arranged at the railway vehicle 12. The position estimator 41 further receives as input data a distance signal 23, which is indicative of a distance 24 traveled by the railway vehicle 12 during its operation. Figure 8 further indicates that reference signals 35 are provided to the position estimator 41. The reference signals 35 are stored in a database 36 and are made available to the position estimator 41 . Figure 8 further shows that the reference signals 35 comprises a deflection sequence 39 which comprises a plurality of signal deflections 40. The measures inductive sensor signal 33 is compared with the plurality of stored reference signals 35 by the P28790PC00 September 2025

[0143] 35 / 47 position estimator 41 further e.g. using the distance signal 23 for determining the current geographical position 37 of the railway vehicle 12 on the railway tracks 37.

[0144] Figure 9 shows the railway vehicle 12 on railway tracks 15. The railway vehicle 12 comprises at least one inductive sensor 38, which is configured to provide the inductive sensor signal 33. Furthermore, the railway vehicle 12 comprises a speed or distance sensor 42, which is configured to provide the distance signal 23. Figure 9 further shows a picture of a possible railway track 15 on which the railway vehicle 12 could run. The picture shows the railway track 15, a railway junction and a metal infrastructure object 34, in particular a metal manhole. Figure 9 further shows the reference signal 35 and I or the measured inductive sensor signal 33 over distance when the railway vehicle passes over the shown railway track 15 in the picture. Figure 9 further shows that the reference signal 35 and I or the measured inductive sensor signal 33 show a deflection sequence 39, comprising a plurality of deflections 40. Figure 9 further indicates that the first deflection 40 of the shown deflection sequence 39 corresponds to the manhole in the picture.

[0145] Figure 10 shows a flow diagram indicating different steps of the method of determining the current geographical position 37 of the railway vehicle 12. In the following paragraphs, described with reference to Figures 8 to 10 is a possible sequence of steps, performed by the position estimator 41 for determining the current geographical position 37 of the railway vehicle 12.

[0146] In step X1 an inductive sensor signal 33 is received, in particular in the position estimator 41 , during the operation of the railway vehicle 12 on the railway track 15, wherein the inductive sensor signal 33 is indicative of at least one of the metal infrastructure objects 34 in vicinity of the railway track 15 just passed by the railway vehicle 12. P28790PC00 September 2025

[0147] 36 / 47

[0148] In step X2 reference signals 35 stored in a database 36 are provided, in particular to the position estimator 41 , wherein the reference signals 35 are linked to a specific geographical location of the railway track 15 of the respective reference signals 35. The reference signals 35 are e.g. obtained in a reference run of a respective vehicle along the railway tracks 15.

[0149] In step X3 the current geographical position 37 of the railway vehicle 12 on the railway track 15 is determined, in particular by the position estimator 41 , by comparing the received inductive sensor signal 33 with the reference signals 35.

[0150] In optional step X4 the distance signal 23 is received, in particular by the position esti- mator 41 , which is indicative of a distance 24 traveled by the railway vehicle 12 during its operation, wherein the distance signal 23 is additionally used for determining X3 the current geographical position 37 of the railway vehicle 12 on the railway track 15.

[0151] In optional step X5, the reference signals 35 are preselected, in particular by the position estimator 41 , for comparison with the expected inductive sensor signal 33 based on at least one previous determined X3 geographical position 37 of the railway vehicle 12 on the railway track 15.

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[0154] LIST OF REFERENCE SYMBOLS

[0155] 1 Steerable bogie 27 Track geometry sensor

[0156] 2 Base 28 Trained neural network

[0157] 3 Frame 30 29 Angular position sensor

[0158] 4 Steering axis 30 Distance signal sensor

[0159] 5 Wheel 31 Database

[0160] 6 T read 32 Processor

[0161] 7 Wheel rotation axis 33 Inductive sensor signal

[0162] 8 Lateral sensor 35 34 Metal infrastructure object

[0163] 9 Steering actuator 35 Reference signal

[0164] 10 Bogie steering control unit 36 Database

[0165] 11 Electrical engine 37 Current geographical posi¬

[0166] 12 Railway vehicle tion

[0167] 13 Chassis 40 38 Inductive Sensor

[0168] 14 Chassis portion 39 Deflection sequence

[0169] 15 Railway track 40 Deflection

[0170] 16 Railway track section 41 Position estimator

[0171] 17 First leading Bogie 42 Speed or distance sensor

[0172] 18 Second leading bogie 45

[0173] 19 Trailing bogie 51 Providing specification data

[0174] 20 Steering angle 52 Receiving angular position

[0175] 21 Specification data signal

[0176] 22 Angular position signal 53 Receiving distance signal

[0177] 23 Distance signal 50 S4 Receiving lateral sensor sig¬

[0178] 24 Traveled distance nal

[0179] 25 Lateral sensor signal S5 Providing track geometry in¬

[0180] 26 Track geometry information formation P28790PC00 September 2025

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[0182] 56 Providing trained neural net- X3 Determining current position work X4 Receiving the distance sig¬

[0183] 57 Determining the steering annal gle X5 Preselecting the reference S8 Assigning steering angle 15 signals

[0184] S9 Control the trailing bogie

[0185] X rolling direction

[0186] X1 Receiving inductive sensor Y lateral direction signal Z vertical direction X2 Providing reference signal 20

Claims

P28790PC00 September 202539 / 47PATENT CLAIMS1. A computer-implemented method of determining a steering angle (20) of a trailing bogie (19) of a railway vehicle (12) guided on a railway track (15), wherein the railway vehicle (12) comprises the trailing bogie (19) and at least one leading bogie (17, 18) arranged, with respect to the direction of travel, in front of the trailing bogie (19), the method comprises the steps of: a. Providing (S1) specification data (21) of the railway vehicle (12), wherein the specification data (21) comprises position information of the trailing bogie (19) and the at least one leading bogie (17, 18) with respect to a chassis (13) of the railway vehicle (12); b. Receiving (S2) an angular position signal (22), which is indicative of an angle between the rolling direction (X) of at least one wheel (5) of the at least one leading bogie (17, 18) and a chassis portion (14) of the railway vehicle (12) at which the respective leading bogie (17, 18) is connected; c. Receiving (S3) a distance signal (23), which is indicative of a distance (24) traveled by the railway vehicle (12) during its operation; d. Determining (S7) the steering angle (20) of the trailing bogie (19) by using the specification data (21), the angular position sensor signal (22) and the distance signal (23).

2. The computer-implemented method according to claim 1 , wherein the railway vehicle (12) comprises a plurality of leading bogies (17, 18) each being arranged in front of the trailing bogie (19) with respect to the direction of travel, wherein receiving (S2) the angular position signal (22) comprises to receive from the plurality ofP28790PC00 September 202540 / 47 leading bogies (17, 18) a respective angular position signal (22), which is indicative of the angle between the rolling direction (X) of at least one wheel (5) of the respective leading bogie (17, 18) and the respective chassis portion (14) of the railway vehicle (12) at which the respective leading bogie (17, 18) is connected, and I or wherein receiving (S3) the distance signal (23) comprises to receive from the plurality of leading bogies (17, 18) a respective distance signal (23), which is indicative of a distance (24) traveled by the railway vehicle (12) during its operation, and wherein the steering angle (20) of the trailing bogie (19) is determined (S7) by using the plurality of the received angular position signals (22) and I or the plurality of the received distance signals (23).

3. The computer-implemented method according to any one of the preceding claims, wherein the specification data (21) comprises information of at least one of: the bogie type, the number of wheelsets per bogie, the position of the at least one wheelsets or wheels at the respective bogie or the degrees of freedom of rotation of the different wheels.

4. The computer-implemented method according to any one of the preceding claims, wherein the method further comprises the step of: a. Receiving (S4) from a lateral sensor (8) of at least one of: the at least one leading bogie (17, 18) or the trailing bogie (19) of the railway vehicle (12), a lateral sensor signal (25), which is indicative of a lateral position of at least one tread (6) of the respective bogie (17, 18, 19) with respect to the railway track (15), and wherein the steering angle (20) of the trailing bogie (19) is determined (S7) by further using the at least one lateral sensor signal (25).P28790PC00 September 202541 / 475. The computer-implemented method according to claim 4, wherein the received lateral sensor signal (25) of the trailing bogie (19) is used to determine the lateral distance between at least one tread (6) of the trailing bogie (19) and the respective rail of the railway track (15), and wherein the steering angle (20) of the trailing bogie (19) is determined such that the lateral distance is kept within a predetermined threshold band.

6. The computer-implemented method according to any one of the preceding claims, wherein the method further comprises the step of: a. Providing (S5) track geometry information (26), which are indicative of at least one of: a curvature, an inclination, lateral distances between the rails of the railway track (15), track switch positions, track crossing positions of the railway track (15) or geographical markers of the railway track (15), and wherein the steering angle (20) of the trailing bogie (19) is determined (S7) by further using the track geometry information (26).

7. The computer-implemented method according to claim 6, wherein the track geometry information (26) is received as sensor signal, from at least one track geometry sensor (27) of the railway vehicle (12).

8. The computer-implemented method according to claim 6, wherein the at least one track geometry sensor (27) of the railway vehicle (12) comprise at least one of: an RFID-sensor, a LIDAR-sensor, a RADAR-sensor, a camera, a force sensor, a magnetic field sensor or a global position sensor.P28790PC00 September 202542 / 479. The computer-implemented method according to any one of the claims 7 to 8, wherein the received sensor signals from at least two of the track geometry sensors (27) are combined with each other to determine the track geometry information (26).

10. The computer-implemented method according to any one of the preceding claims, wherein the step of determining the steering angle (S7) of the trailing bogie (19) comprises that the received angular position signal (22) is transformed into the steering angle for the trailing bogie (19) in dependence of at least the specification data (21), the distance signal (23) and a transformation algorithm, wherein the transformation algorithm causes that the tread (6) of at least one wheel (5) of the trailing bogie (19), when being steered by using the determined steering angle (20), is at least in specific railway track sections (16) differently aligned to the railway track (15) compared to the tread (6) of the leading bogie (17, 18) when it was running along the same railway track section (16).11 . The computer-implemented method according to any one of the preceding claims, wherein the method further comprises the steps of: a. Assigning (S8) the determined steering angle (20) of the trailing bogie (19) to a railway track section (16); b. Determining (S7) the steering angle (20) of the trailing bogie (19) by further using the assigned steering angle (20) when the railway vehicle (12) passes the respective railway track section (16) again.

12. The computer-implemented method according to any of the preceding claims, wherein the method further comprises a step of:P28790PC00 September 202543 / 47 a. Determining (S7) a steering angle (20) of the at least one leading bogie (17, 18) by using the determined steering angle (20) of the trailing bogie (19) and I or at least one leading bogie (17, 18).

13. The computer-implemented method according to claim 12, wherein the step of determining the steering angle (20) of the at least one leading bogie (17, 18) comprises the following steps: a. Assigning (S8) the determined the steering angle (20) of the at least one leading bogie (19) to a railway track section (16); b. Determining (S7) the steering angle (20) of the at least one leading bogie (17, 18) by further using the assigned steering angle (20) when the railway vehicle passes the respective railway track section (16) again.

14. A bogie steering control unit (10), which is configured to determine a steering angle (20) of a trailing bogie (19) of a railway vehicle (12) guided on a railway track (15), wherein the railway vehicle (12) comprises the trailing bogie (19) and at least one leading bogie (17, 18) arranged in front of the trailing bogie (19) with respect to the direction of travel, wherein the bogie steering control unit (10) comprises a processor (32), which is configured to: a. Access (S1) specification data (21) of the railway vehicle (12), wherein the specification data (21) comprises position information of the trailing bogie (19) and the at least one leading bogie (17, 18) with respect to a chassis (14) of the railway vehicle (12); b. Receive (S2) an angular position signal (22), which is indicative of an angle between the rolling direction (X) of at least one wheel (5) of the at leastP28790PC00 September 202544 / 47 one leading bogie (17, 18) and a chassis portion (14) of the railway vehicle (12) at which the respective leading bogie (17, 18) is connected; c. Receive (S3) a distance signal (23), which is indicative of a distance (24) traveled by the railway vehicle (12) during its operation; d. Determining (S4) the steering angle (20) of the trailing bogie (19) by using the specification data (21), the angular position signal (22) and the distance signal (23).

15. The bogie steering control unit (10) according to claim 14, wherein the bogie steering control unit (10) is configured to execute any method step as claimed in any one of the preceding claims 2 to 13.

16. A railway vehicle (12), comprising: a. a trailing bogie (19) and at least one leading bogie (17, 18) arranged in front of the trailing bogie (19) with respect to the direction of travel; b. a bogie steering control unit (10) according to claim 13 or 14, which is configured to determine the steering angle (20) of the trailing bogie (19); c. a steering actuator (9), which is configured to steer the trailing bogie (19) with respect to a chassis (13) of the railway vehicle (12) by using the determined steering angle (20).

17. The computer-implemented method according to any one of the preceding claims, wherein the method further comprises the steps of:P28790PC00 September 202545 / 47 a. Receiving (X1) an inductive sensor signal (33) during the operation of the railway vehicle (12) on the railway track (15), wherein the inductive sensor signal (33) is indicative of at least one metal infrastructure object (34) in vicinity of the railway track (15) just passed; b. Providing (X2) reference signals (35) stored in a database (36), wherein the reference signals (35) are linked to a specific geographical location of the railway track (15) of the respective reference signals (35); c. Determining (X3) the current geographical position (37) of the railway vehicle (12) on the railway track (15), by comparing the received inductive sensor signal (33) with the reference signals (35).

18. The computer-implemented method according to claim 17, wherein the determined current geographical position (37) of the railway vehicle (12) is further used to determine the steering angle (20) of the trailing bogie (19).

19. The computer-implemented method according to any one of the claim 17 to 18, wherein the reference signals (35) are recorded by a respective reference run along the railway track (15) using an inductive sensor (38) and a position measurement device.

20. The computer-implemented method according to any one of the claims 17 to 19, wherein the metal infrastructure object (34) in vicinity of the railway track (15), which is measured, comprises at least one of: railway track infrastructure, metal covers on the ground, manholes or specific metal objects.

21. The computer-implemented method according to any one of the claims 17 to 20, wherein the method further comprises the step of:P28790PC00 September 202546 / 47 a. Receiving (X4) the distance signal (23), which is indicative of a distance (24) traveled by the railway vehicle (12) during its operation, wherein the distance signal (23) is additionally used for determining (X3) the current geographical position (37) of the railway vehicle (12) on the railway track (15).

22. The computer-implemented method according to any one of the claims 17 to 21 , wherein the inductive sensor signal (33), which is compared to the reference signals (35) comprises a deflection sequence (39), wherein each deflection (40) corresponds to one of the metal infrastructure objects (34), and wherein the reference signals (35) also comprises a respective reference deflection sequence.

23. The computer-implemented method according to any one of the claims 17 to 22, wherein the reference signals (35) form a reference map of the entire railway network of the railway tracks (15) on which the railway vehicle (12) is operating, thereby enabling to determine the current geographical position (37) of the railway vehicle (12) of the entire railway network.

24. The computer-implemented method according to any one of the claims 17 to 23, wherein the method further comprises the step of: a. Preselecting (X5) the reference signals (35) for comparison with the expected inductive sensor signal (33) based on at least one previous determined (X3) geographical position (37) of the railway vehicle (12) on the railway track (15).

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