Method and device for determining longitudinal forces in a track rail

Abstract

The method for determining the longitudinal force in the track rail (2) is the test load (F P ), moving at least one rail portion (6) of the track rail (2) from an initial configuration to a test configuration by applying a test load (F P ), and determining a longitudinal force on the at least one track rail (2) based on the at least one force measurement, wherein upon detecting the at least one force measurement, at least one track sleeper (8) is fixed to the rail portion (6).

Description

[Technical field]

[0001] The present invention relates to a method for determining longitudinal forces on a track rail, and further to a device for carrying out the method.

[0002] A method for determining the longitudinal forces on a track rail is known from obvious previous use, in which the track rail, completely removed from the track sleepers, is lifted vertically. The test load required for this is determined. On the basis of this test load, the longitudinal forces present on the track rail are determined. A disadvantage is that the removal of the track rail from the track sleepers is time-consuming and cost-intensive. During this period, the track is not used for rail traffic. In order to avoid distortion of the track rail when it is removed from the track sleepers, this method can furthermore only be carried out if the temperature of the track rail is below the neutral temperature.

[0003] The object of the invention is, in particular, to provide an improved method for determining longitudinal forces on a track rail, which can be implemented in a particularly flexible, time-efficient and economical manner.

[0004] This problem is solved by a method with the features of claim 1. It has been found that if, during the detection of the at least one force measurement value, at least one of the track sleepers is fixed to the rail section which is displaced by applying a test load between the initial position and the test position, a particularly flexible, time-efficient and economical determination of the longitudinal forces on the at least one track rail can be performed on the basis of the at least one force measurement value correlated with the test load. By keeping the at least one track sleeper fixed to the track rail, removal or formation of a bond can be omitted. The closing time of the track section can be reduced or completely avoided. Distortions of the track rail, in particular at rail temperatures above the neutral temperature, due to, for example, unexpectedly high or rapidly rising ambient temperatures, can be reliably prevented by the fact that the support of the track rail remains by the track sleepers.

[0005] Longitudinal forces on the track rail are understood in the following to mean stresses present in the track rail and loads acting on the track rail acting along the longitudinal direction of the track rail. Such loads are, for example, external forces and / or temperatures, in particular temperature changes. Corresponding stresses include tensions and strains.

[0006] A test load is understood as a force which causes the movement of at least one rail section of the track rail into the test arrangement and / or the holding of the rail section in the test arrangement. The test load may comprise at least one point load and / or at least one line load. The test load preferably acts on the rail section in the form of individual point loads. The at least one point load can be generated, for example, by means of an actuator, in particular a hydraulic actuator, and / or can be transferred to the respective rail section by means of a gripper.

[0007] A rail portion is understood to be a portion of at least one track rail that is displaced in the test configuration relative to the initial configuration. The rail portion is along the longitudinal direction of the track and overlaps at least the location where the test load is applied on the at least one track rail. The rail portion is preferably defined by a portion of at least one track rail that is along the longitudinal direction and is not displaced in the test configuration relative to the initial configuration.

[0008] The track preferably includes track sleepers and two track rails arranged parallel to each other and spaced apart according to the track gauge. According to one aspect of the invention, the application of a test load causes the movement of two parallel rail sections of the two track rails, which completely overlap each other in the longitudinal direction of the track. In particular, track sections corresponding to the longitudinal extension of these rail sections can be moved from an initial position to a test position by applying a test load.

[0009] The movement of the rail section of the at least one track rail preferably takes place perpendicular to the longitudinal direction of the track, in particular horizontally and / or vertically, in particular only in one of these directions. For this purpose, the force measurement value can have a horizontal and / or vertical component. The detection of the at least one force measurement value can take place by means of at least one force measuring means, in particular at least one load cell.

[0010] At least one track sleeper fixed to the rail section is preferably moved from an initial position to a test position, in particular together with the rail section, by applying a test load. At least two, in particular at least three, in particular at least five of the track sleepers are preferably fixed to the rail section of the at least one track rail.

[0011] According to another aspect of the invention, the rail sections, in particular the paired rail sections and / or the track are moved from an initial position to at least two, in particular at least three, in particular at least five and / or up to ten test positions. In these test positions, a force measurement value can be determined in each case, which is correlated with the respective test load. From this, the longitudinal force on the at least one track rail can be determined. In particular, the course of the at least one force measurement value during the movement to the at least one test position can be determined. Based on the course of the at least one force measurement value, the longitudinal force on the at least one track rail can be determined a number of times. An average value of the longitudinal forces determined a number of times can be formed. This allows the longitudinal force to be determined particularly reliably and precisely.

[0012] According to another aspect of the invention, the determination of the longitudinal force can furthermore be based on the weight of the at least one track rail and / or of the at least one track sleeper fixed to the rail section. The weight of the track rail can, for example, be assumed as a line load. The weight of the at least one track sleeper can likewise be incorporated into the determination of the longitudinal force approximately as a line load and / or in the form of an individual point load. This allows the longitudinal force to be determined particularly accurately.

[0013] According to one aspect of the invention, the movement from the initial position to the test position and / or the detection of the at least one force measurement value is performed at rail temperatures above and / or below a neutral temperature. A neutral temperature is understood as a rail temperature at which the longitudinal forces, in particular the longitudinal expansion, at the respective track rail are equal to zero. This advantageously achieves that the method can also be performed at high ambient temperatures and / or without knowing the neutral temperature. This is made possible in particular by the fact that there is no need to remove the track rail from the track sleeper, whereby the track rail remains fixed in its position, thereby avoiding distortions transverse to the longitudinal direction. This makes the method extremely robust against high rail temperatures, for example due to inaccurate weather forecasts or assembly delays.

[0014] According to another aspect of the invention, a temperature measurement value is detected which correlates with the temperature of at least one track rail. The temperature measurement value is preferably detected in a contact and / or contactless manner, in particular by means of a pyrometer. The temperature measurement value detection can include averaging over a number of individual measurements. The temperature measurement value is preferably detected in the area of ​​the rail section and / or at the time of detecting at least one force measurement value. A positional and temporal correlation, in particular a combined recording, of the longitudinal force and the associated temperature measurement value is preferably performed.

[0015] The method according to claim 2 can be carried out in a particularly time-efficient and economical manner. The track is preferably fully assembled. The method can be carried out after the production of the track, in particular before the first commissioning for a traveling operation and / or after an already used in a traveling operation, in particular during a maintenance procedure. The fastening of the track rails to all track sleepers preferably remains complete, in particular compared to the state provided for the traveling operation. This allows the closing time of the track section to be shortened, in particular avoided. Furthermore, the necessary assembly effort is reduced.

[0016] The method according to claim 3 can be used in a particularly flexible way. The neutral temperature is preferably determined on the basis of at least one temperature measurement and the determined longitudinal forces, in particular the longitudinal expansion. Corresponding to a known relationship, the temperature difference required to achieve a certain longitudinal expansion can be estimated via the thermal expansion coefficient of the track rail in the longitudinal direction. Via this neutral temperature, the stresses in the track rail can be particularly clearly represented and compared. In particular, a neutral temperature boundary value can be set. When the neutral temperature boundary value is exceeded and / or below, it is preferably determined that a maintenance procedure is required. As a result, the normal running operation can be limited or stopped.

[0017] The method according to claim 4 ensures the determination of the longitudinal force in a particularly reliable and accurate manner. The at least one distance measurement value can be determined at any position along the rail section, but preferably in the area, in particular the location, of the test load acting on the rail section. The at least one distance measurement value can be correlated with the vertical and / or horizontal displacement of the rail section between the initial position and the test position. Alternatively to the detection of the distance measurement value, the rail section can be moved to a predefined test position, for example by means of a moving mechanism with fixed end stops, in particular by means of a toggle lever.

[0018] The method according to claim 5 is particularly time-efficient and economical to implement. A lifting and straightening unit is understood as a device for moving the track from an actual track configuration to a target track configuration. The lifting and straightening unit is preferably configured to move the track transversely to the longitudinal direction, in particular vertically and / or horizontally. Lifting and straightening units are often already available for track construction. This makes it possible to dispense with the procurement of additional devices for moving the rail sections. The method can in particular be implemented in parallel with a method for lifting and / or moving the track to a target track configuration.

[0019] The method according to claim 6 is particularly time-efficient and economical to implement. The compaction of the track ballast underlying the rail section is preferably performed in a processing position of the rail section, which is at least partially reached by moving from an initial position to a test position. The track lifting required for the compaction process is thereby available in parallel with the determination of the longitudinal forces. The detection of the at least one force measurement value is preferably performed in a time-decoupled manner from the compaction process, in particular from the penetration of the tamping tool into the ballast bed. This makes it possible to avoid measurement errors, in particular due to disruptive influences on the detection of the force measurements.

[0020] The method according to claim 7 ensures that the longitudinal forces are determined in a particularly reliable and accurate manner. By taking into account the influence of the ballast stiffness on the determination of the longitudinal forces, it is ensured that the longitudinal forces can be determined reliably and accurately, in particular when the properties of the track ballast differ. The ballast stiffness can be incorporated into a ballast model, for example based on the ballast module method according to Winkler.

[0021] The method according to claim 8 is particularly flexible in application and ensures the determination of the longitudinal forces in a particularly accurate manner. Preferably, ballast measurements are detected which are correlated with the ballast stiffness of the track ballast underlying the rail section. The ballast measurements can be used for the determination of the longitudinal forces. This allows the influence of different ballast stiffnesses on the determination of the longitudinal forces to be taken into account. The ballast measurements can be determined, for example, in the form of compaction measurements, on the basis of measurements which are detected in particular by means of a tamping unit and / or on the basis of at least one force measurement which is correlated with the test load. The compaction measurements are in particular correlated with the reaction forces between the track ballast and the tamping tool of the tamping unit during the compaction of the track ballast.

[0022] The method according to claim 9 ensures a particularly flexible and time-efficient determination of the longitudinal forces. A comparatively small computing power is required to carry out the method. The determination of the longitudinal forces based on at least one force measurement value can be carried out in particular by means of an evaluation device with a conventional microcontroller and / or a conventional desktop PC. Suitable analysis methods include, for example, a structural model in which at least one track rail, in particular together with a track sleeper, is modeled as a beam, in particular as an elastically embedded beam. The corresponding analysis methods can be based, for example, on the linear beam theory according to Bernoulli or on the nonlinear beam theory.

[0023] According to one, particularly independent aspect of the invention, the determination of the longitudinal forces on the track rail is performed taking into account the track bed stiffness of the track ballast underlying the corresponding rail section, in particular the longitudinal forces can be determined based on the properties of the track sleepers, in particular the track sleepers connected to at least one track rail, in particular the weight of the track sleepers.

[0024] The method according to claim 10 ensures the determination of the longitudinal forces in a particularly flexible and robust manner. The determination of the longitudinal forces at the track rail is based on at least one force measurement value correlated with a test load moving the rail section from an initial position to a test position and is based on a finite element method (FEM), which is in particular an independent aspect of the invention. The FEM can be used indirectly for the determination of the longitudinal forces. Alternatively, the FEM can be used to determine the parameters of an analytical method for determining the longitudinal forces. The corresponding method is also called a semi-analytical method. The FEM is preferably based on a modeling of at least one track rail with Lagrange polynomials, more preferably with non-uniform rational B-splines (NURBS). A particularly accurate determination of the longitudinal forces at the track rail is made possible by an Isogeometrische Analysis (IGA) of a structural model of the track and / or the track ballast.

[0025] The method according to claim 11 ensures a particularly robust and accurate determination of the longitudinal force. The determination of the longitudinal force is preferably based on at least two, in particular at least three, in particular at least five, in particular at least ten force measurements. The force measurements are preferably detected at the same and / or different positions along the longitudinal direction of the track. An average value can be formed over a number of force measurements. Furthermore, the number of known parameters required to calculate the longitudinal force can be reduced. The method is particularly flexible to use and gives particularly accurate results.

[0026] Another object of the invention is to create an improved device for determining the longitudinal forces on a track rail, in particular for carrying out the method described above, which can be used in a particularly flexible, time-efficient and economical way.

[0027] This problem is solved by an apparatus with the features of claim 12. The advantages of the apparatus correspond to those of the method described above. The apparatus is preferably improved by at least one of the features described above in connection with the method. The testing apparatus preferably comprises at least one test actuator, in particular a lifting actuator and / or a straightening actuator, for moving at least one track rail, in particular two track rails, in particular respective rail sections of the track sections, from an initial position to a test position by applying a test load. The at least one test actuator can be configured to move the rail sections vertically and / or horizontally.

[0028] The testing device may preferably comprise at least one force measuring means for detecting at least one force measurement value.The testing device may comprise at least one distance measuring means for detecting at least one distance measurement value.

[0029] According to one aspect of the invention, the apparatus is configured as a track construction machine, particularly for making and / or maintaining track.

[0030] The device according to claim 13 can be used in a particularly flexible and time-efficient manner. The vehicle can be configured as a bi-directional vehicle. The vehicle can have a driving motor or can be configured as a trailer vehicle without a driving device. The test device is preferably permanently or removably attached to the vehicle. The test device can have a coupling for removably connecting to the vehicle.

[0031] The device according to claim 14 can be used particularly flexibly and economically. The test device can be used to determine the longitudinal forces preferably in the rail sections on which the running cars are arranged, in particular in rail sections overlapping the running cars along the longitudinal direction of the track. Additionally or alternatively, the device can be used to determine the longitudinal forces in rail sections of adjacent tracks. For this purpose, the device can have a positioning device coupled to the running cars for moving the test device perpendicular to the track.

[0032] The device according to claim 15 is particularly flexible and economical in operation. At least one test actuator for moving the rail section from the initial position to the test position is preferably also used for determining the longitudinal forces, in particular for applying a test load, and also for compacting the track ballast underlying the rail section. A separate lifting actuator can be omitted. The compaction of the track ballast and the determination of the longitudinal forces on the track rail can be at least partially parallelized in time.

[0033] Further features, details and advantages of the invention emerge from the following description of an embodiment based on the drawings. [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is a side view showing an apparatus for determining longitudinal forces in a rail having a test device for moving a rail section, the rail section being placed in an initial position, the apparatus being in particular a track construction machine. [Diagram 2] FIG. 2 is a side view of the apparatus of FIG. 1 with a test load being applied to the rail section by the testing apparatus and the rail section being positioned in a test position. [Diagram 3] FIG. 3 shows a structural model of the rail section of FIG. 2 for determining the longitudinal force based on at least one force measurement. [Figure 4] FIG. 4 is a free cross-sectional view of a portion of the structural model of FIG. 3 with a cutting force acting on the cutting boundary. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] 1 to 4, one embodiment of an apparatus 1 for determining a longitudinal force on a track rail 2 will be described. The apparatus 1 has a traveling vehicle 3 for traveling on a track 4, and a test device 5 for moving a rail section 6 of at least one track rail 2 and detecting at least one force measurement value.

[0036] The track 4 is arranged on a track ballast 7, in particular a ballast track bed. Two track rails 2 arranged parallel to and spaced apart from each other are fixed to track sleepers 8. The track sleepers 8 rest on the track ballast 7. The track 4 has an assembled state in which it is possible to run.

[0037] The traveling vehicle 3 is disposed on the track rail 2 to travel on the track 4. The traveling vehicle 3 has two bogies 9 and a support frame 10 attached to the bogies 9. The bogies 9 have wheels 11 that can be rail-guided. A driving force required for movement along the track 4 is applied to the traveling vehicle 3 by at least one traveling prime mover 12.

[0038] The test device 5 comprises a lifting and straightening unit 13, which has a gripper 14 for reversibly gripping the track rail 2. For displacing the rail section 6 along the vertical direction z, one lifting actuator 15 is provided for each track rail 2. The straightening actuators, not shown, are configured to displace at least one track rail 2 in a horizontal direction y, which is oriented perpendicularly to the longitudinal direction x of the track 4. The respective lifting actuator 15 and the respective straightening actuator are configured as fluidic, in particular hydraulic, actuators. The lifting actuator 15 and / or the straightening actuator preferably apply a test load F to the respective track rail 2, in particular via the gripper 14. P The present invention is configured to cause the following:

[0039] The lifting and straightening unit 13 has a force measuring means 16, which measures a test load F for moving at least one rail section 6 between an initial position and a test position. P The force measuring means 16 are preferably configured as load cells. The lifting and straightening unit 13 further comprises a distance measuring means for each lifting actuator 15 and for each straightening actuator for detecting a respective distance measurement value w, which is correlated with a vertical and / or horizontal displacement of at least one track rail 2, in particular of the rail section 6, in particular between the initial position and the test position in the region of the gripper 14. Each distance measuring means 17 preferably comprises at least one displacement sensor, in particular a potentiometer, for detecting the displacement of the respective lifting actuator 15 and / or the respective straightening actuator.

[0040] The lifting and straightening units 13 are mounted on a support frame 10. A supply 18 of the device 1 provides the electrical power required to operate the device 1 and the fluid power, in particular the hydraulic power required to operate the respective lifting actuators 15 and straightening actuators.

[0041] The device 1 comprises a tamping unit 19 for compacting the track ballast 7 underlying the track 4. The tamping unit 19 is mounted via a vertically oriented linear guide 20 on a unit support 21. The unit support 21 is fixed to the support frame 10. A vertical drive 22 is configured to move the tamping unit 19 along the linear guide 20.

[0042] The tamping unit 19 comprises two tamping tools 23 and a tamping drive 24. The tamping drive 24 is configured to pivot the tamping tools 23 about a horizontal tamping tool axis 25. By means of the tamping drive 24, a combined pivoting and vibration movement is transferred to the tamping tools 23 about the respective tamping tool axis 25. The tamping drive 24 includes an electric and / or fluid, in particular hydraulic, actuator. The tamping drive 24 is connected to a supply device 18 for power transfer. By means of the supply device 18, the necessary power and / or fluid output is provided to the tamping unit 19.

[0043] The device 1 comprises a control device 26, which is in signal connection with the lifting and straightening unit 13, with the tamping unit 19 and in particular also with the traveling vehicle 3 and with the feed device 18. The control device 26 is configured to control the positioning of the track 4, in particular of the at least one track rail 2, by means of the lifting and straightening unit 13. The control device 26 is further configured to control the compaction of the track ballast 7 by means of the tamping unit 19. The control device 26 is in particular configured to control the feeding device 18 and / or the travelling movement of the traveling vehicle 3 along the track 4.

[0044] The tamping unit 19 has a reaction force measuring means (not shown) for detecting reaction force measurements, which are correlated with the ballast forces acting between the track ballast 7 and the tamping tool 23. The reaction force measuring means can be configured, for example, as a pressure sensor for detecting the hydraulic pressure in a hydraulic actuator of the tamping drive 24. The reaction force measuring means is preferably configured for detecting reaction force measurements, which occur when the at least one tamping tool 23 penetrates the track ballast 7, in particular vertically, and / or during a periodic movement, in particular a vibration movement of the at least one tamping tool 23 between the at least one tamping tool 23 and the track ballast 7. The reaction force measurements can be correlated correspondingly with the penetration forces acting on the at least one tamping tool 23 and / or with the vibration forces acting on the at least one tamping tool 23 during compaction.

[0045] The device 1 further comprises a temperature measuring means 27 for determining the temperature of the at least one track rail 2. The temperature measuring means 27 is configured as a pyrometer. The temperature measuring means 27 is signal-connected to the control device 26.

[0046] The evaluation device 28 of the apparatus 1 is configured to determine the longitudinal force on at least one track rail 2 based on the signals of the force measuring means 16, in particular further based on the signals of the respective distance measuring means 17, reaction force measuring means and / or temperature measuring means 27.

[0047] The manner of operation of the device 1 for determining the longitudinal forces on a track rail 2 is as follows.

[0048] In FIG. 1 the device 1 is shown in a first working position. In the first working position the device 1 is arranged on the track 4. The tamping tool 23 of the tamping unit 19 is not engaged with the track ballast 7. The two paired arranged rail sections 6 overlap the lifting and straightening unit 13, the two grippers 14 and the tamping unit 19 along the longitudinal direction x. The lifting and straightening unit 13 is connected to the rail sections 6 via the two grippers 14 in a form-locking manner. In the first working position the lifting and straightening unit 13 does not exert any force on the track 4, in particular on the rail sections 6 of the track rail 2. The two track rails 2, in particular on the rail sections 6, are in an initial position.

[0049] To determine the longitudinal forces on the two track rails 2, the control device 26 supplies signals to the supply device 18 for activating the two lifting actuators 15. The lifting actuators 15 are connected to the test load F P and the two grippers 14 together with the rail sections 6 are moved upwards in the vertical direction z. The device 1 is in the second working position shown in Figure 2. The two track rails 2, in particular the rail sections 6, are in the test position.

[0050] The vertical displacement w is the test load F P is determined by the distance of the respective rail section 6 at the point where the respective gripper 14 is introduced, i.e. between the initial position and the test position. By means of the respective distance measuring means 17 of the lifting and straightening unit 13, a distance measurement value is detected which correlates with the displacement of the associated lifting actuator 15 and correspondingly with the vertical displacement w. By means of the force measuring means 16, a force measurement value is detected which corresponds to the test load F acting on the respective track rail 2 via the respective gripper 14. P Correlated with.

[0051] The track rail 2 is fixed to the track sleepers 8 in the test arrangement, in particular when detecting at least one force measurement value. In the test arrangement, the track 4 is in a runnable assembled state, in particular in the region of at least one rail section 6.

[0052] By means of the temperature measuring means 27 , in particular in a contactless manner, temperature measurements are detected which correlate with the temperature of the respective track rail 2 .

[0053] The control device 26 provides a signal to start the compaction of the track ballast 7. The tamping unit 19 is lowered by means of the vertical drive 22. The tamping tools 23 penetrate the track ballast 7. The tamping tools 23 are pivoted about the respective tamping tool axes 25 and are subjected to a vibratory movement. The ballast of the track ballast 7 is compacted in the area below the tamping unit 19. When compacting the track ballast 7, reaction force measurements are recorded by means of the reaction force measuring means. The compaction process is ended and the tamping unit 19 is moved again into the first working position.

[0054] The longitudinal force, in particular the normal force N, on the track rail 2 is determined on the basis of the detected force, distance, temperature and reaction force measurements. g The evaluation device 28 further stores information about the resulting longitudinal weight q of the track sleeper 8 along the longitudinal direction x. s The longitudinal weight q of the track sleeper 8 is included. s is determined in particular by the average weight of each individual track sleeper 8 in the rail section 6 and the average distance l between the central longitudinal axes of two adjacent track sleepers 8 s The evaluation device 28 also stores the elastic modulus E, the cross-sectional area A and the thermal expansion coefficient α T , as well as information about the area moment of inertia I of the track rail 2 about the horizontal transverse axis y and / or about the vertical axis z. The longitudinal forces on the at least one track rail 2 are preferably determined based on the area moment of inertia I of the track rail 2 about the horizontal transverse axis y when the rail section 6 moves in the vertical direction z and / or based on the area moment of inertia I of the track rail 2 about the vertical axis z when the rail section 6 moves in the horizontal direction y.

[0055] The ballast module k of the track ballast 7 is stored in the evaluation device 28. The ballast module k corresponds to the stiffness of the track ballast 7 in the vertical direction z. The ballast module k is determined and specifically adapted on the basis of reaction force measurements.

[0056] Based on the information explained above, the longitudinal forces in the track rail 2, in particular the normal forces N and normal stresses σ N , and / or longitudinal expansion ε Ν is calculated, which according to the first embodiment is carried out solely on the basis of the FEM model stored in the evaluation device 28.

[0057] Furthermore, the neutral temperature T N Identify the neutral temperature T N is understood to be the temperature at which the longitudinal force, in particular the normal force N, at the track rail 2 becomes zero. For this purpose, a test temperature T P The neutral temperature T of each rail section 6 is determined. N is now specified as follows: T N =T P +N / EAα T It is.

[0058] Test temperature T P Temperature measurements are taken using the temperature measuring means 27, preferably multiple times, during each pass over the rail section 6 in order to determine the test temperature T P It is possible to determine an average value which allows a particularly accurate determination of the temperature. By averaging, local temperature fluctuations and measurement deviations can be compensated for.

[0059] According to an alternative embodiment, the longitudinal forces, in particular the normal forces N and normal stresses σ at the respective track rails 2 N , and longitudinal expansion ε Νcan be determined based on analytical methods. Each track rail 2 is modeled as an elastically embedded beam based on the linear beam theory according to Bernoulli. The track ballast is modeled based on the known ballast module method according to Winkler. The boundary value problem for the vertical displacement w along the longitudinal direction x can be expressed as follows:

number

[0060] The resting point of the wheel 11 closest to the lifting and straightening unit 13 is considered as a fixed bearing in the longitudinal direction x, from which

number

[0061] F R1 and F R2 is the vertical lateral force acting on the track rail 2 at the wheel 11. γ is

number

[0062] The track bed parameter λ represents the transition between the area of ​​the rail section 6 resting on the track ballast 7 and the area of ​​the rail section 6 not in contact with the track ballast 7. Preferably, the track bed parameter λ is assumed to be much larger than the value occurring at the maximum of the vertical displacement w. To determine the vertical displacement w(x), the above differential equation can be solved numerically. On this basis, the lateral force Q A =Q(x=x A ), Q B =Q(x=x B ) is equal to zero A and x B At these positions, the track rail angles α, β corresponding to the inclination of the track rail 2 are determined as follows, i.e.

number

[0063] Due to the balance of forces in the vertical direction, the normal force N on a specific object is

number

[0064] Alternatively, the track rail angles α, β can be approximately determined as the quotient of the vertical displacement w and an empirically determined length value, which is the distance between the position x A ,x B The normal stress σ is based on the normal force N. N can be specified as follows: σ N =N / A It is.

[0065] Longitudinal expansion ε Ν can be calculated as follows: ε N =N / EA It is.

[0066] Preferably, the test load F P At least one force measurement value, which correlates with the vertical displacement w, is detected at at least two different vertical displacements w. In particular, the course of the at least one force measurement value over the vertical displacement w can be determined. This allows the longitudinal force at the respective track rail 2 to be determined several times, in particular during the movement of the rail section 6 between the initial position and the test position. By forming an average value over these several longitudinal forces, the accuracy can be increased. This further allows the weight of the respective track rail 2 and / or track sleeper 8 to be estimated. This allows the longitudinal force at the track rail 2 to be determined particularly reliably and accurately.

[0067] Advantageously, a computer program product is provided for carrying out the above-described method, which may be stored in a storage unit, in particular in the evaluation device 28.

[0068] Due to the fact that the method can be carried out in the runnable assembled state of the track 4, the determination of the longitudinal forces on the track rail 2 can be carried out particularly time-efficiently and economically. At least one track sleeper 8 fixed to the rail section 6 is taken into account in determining the longitudinal forces, in particular by taking into account its weight and the track ballast 7 acting on it, as explained above. Disconnecting the connection between the track rail 2 and the track sleeper 8 in order to determine the longitudinal forces can be avoided. A non-destructive test of the track 4 is made possible. The method in particular allows the determination of the longitudinal forces at a neutral temperature T N and test temperature T P In particular, the method can be carried out without depending on the difference between the test temperature T P is the neutral temperature T N 4. The reason is that there is no need to worry about the track rail 2 moving relative to the track sleepers 8.

[0069] Due to the fact that the method is carried out by means of the device 1, in particular by means of a track construction machine, the determination of the longitudinal forces can be carried out particularly economically. The corresponding device 1 has a particularly wide range of applications. The compaction of the track ballast 7 and the determination of the longitudinal forces can be carried out by means of the device 1 at least partly in parallel and thus particularly time-efficiently.

Claims

1. A method for determining longitudinal forces in a track rail (2), comprising: 1.1 Test load (F Ｐ moving at least one rail section (6) of said track rail (2) from an initial position to a test position by applying a force; 1.2 In the test configuration, the test load (F Ｐ detecting at least one force measurement that correlates with the force of the force sensor; 1.3 determining the longitudinal force on at least one of the track rails (2) based on at least one of the force measurements; In a method having 1.4 Fixing at least one track sleeper (8) to the rail section (6) when detecting at least one of the force measurements. A method characterized by:

2. 2. The method according to claim 1, wherein the rail section (6) has a movable assembly state when detecting at least one of the force measurements.

3. Based on the longitudinal force, the neutral temperature (T Ｎ 3. The method according to claim 1, wherein the first and second digits are determined as follows:

4. 2. The method according to claim 1, characterized in that at least one distance measurement correlated with a displacement (w) of at least one of the track rails (2) between the initial position and the test position is detected.

5. 2. A method according to claim 1, characterized in that the movement is carried out using a lifting and straightening unit (13) of the track construction machine (1).

6. 2. A method according to claim 1, characterized in that the track ballast (7) underlying the rail section (6) is tamped down.

7. 2. The method according to claim 1, characterized in that the longitudinal force is determined taking into account the ballast stiffness (k) of the track ballast (7) underlying the rail section (6).

8. based on at least one compaction measurement detected during compaction of the track ballast (7) and / or based on the test load (F Ｐ 8. The method of claim 7, further comprising determining the ballast stiffness (k) based on at least one of the force measurements correlated with a rolling resistance (RRS) of the track.

9. The method of claim 1 , wherein the determination of the longitudinal force is performed using analytical techniques.

10. The method of claim 1 , wherein the determination of the longitudinal force is performed using a finite element method.

11. Test load (F Ｐ 2. The method of claim 1, further comprising determining the longitudinal force based on at least two of the force measurements correlating with a force of the longitudinal force.

12. 2. An apparatus (1) for carrying out the method according to claim 1, characterized in that it comprises a test device (5) for moving the rail section (6) and for detecting at least one of the force measurements.

13. 13. Apparatus (1) according to claim 12, characterized in that it comprises a vehicle (3) for travelling on a track (4), the testing device (5) being fixed to the vehicle (3).

14. The device (1) according to claim 13, characterized in that the device (1) is configured so that the rail portion (6) of the track rail (2) supporting the traveling vehicle (3) is movable by the testing device (5).

15. 15. Device (1) according to any one of claims 12 to 14, characterized in that it comprises a tamping unit (19) for compacting the track ballast (7) underlying the rail section (6).

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