Ghost train detection

Abstract

The invention relates, inter alia, to a method for ghost train detection within the context of operating a railway track system (10). According to the invention, in the method: - the occupancy status of a track section (20) is monitored using a track-section monitoring device (30) having a signal processing time (Tv), and this track section is reported as free or occupied; - prior to a rail vehicle (50) entering the track section (20) which has been reported as free or after a rail vehicle (50) has exited the track section (20), the region (B) between the rail vehicle (50) and an optically detectable marking (70, 71, 72) which has been installed in the track section (20) or at an end (21, 22) of the track section (20) is monitored by means of at least one camera (81, 82); and - the track section (20) and the region (B) between the marking (70, 71, 72) and the rail vehicle (50) are reported as unoccupied by a ghost train when both, for a specified minimum observation time period which is at least as long as the signal processing time (Tv) of the track-section monitoring device (30), camera signals (KS) from the camera (81, 82) indicate that the region (B) between the rail vehicle (50) and the marking (70, 71, 72) is unoccupied and, at least at the end of the minimum observation time period, the track-section monitoring device (30) reports the track section (20) as free.

Description

[0001] Description

[0002] Ghost train recognition

[0003] The invention relates to a method for detecting ghost trains during the operation of a railway track system.

[0004] The term ghost train refers to a rail vehicle whose existence on the track system is unknown on the line side, for example on the control center or signal box side, and which is therefore also unknown to the rail vehicles known to be running on the railway track system.

[0005] The invention is based on the object of specifying a method for ghost train detection which enables simple ghost train detection by including a track section monitoring device.

[0006] This object is achieved according to the invention by a method having the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the subclaims.

[0007] According to the invention, the method comprises monitoring a track section with a track section monitoring device having a signal processing time to determine its occupancy status and reporting it as free or occupied. Before a rail vehicle enters the track section reported as free or after leaving the track section, the area between the rail vehicle and an optically recognizable marking applied in the track section or at one end of the track section is monitored with at least one camera. The track section and the area between the marking and the rail vehicle are reported as free of ghost trains if, for a predetermined minimum observation period which is at least as long as the signal processing time of the track section monitoring device,Camera signals from the camera indicate the area between the rail vehicle and the marking as unoccupied and at least upon expiry of the minimum observation period, the track section monitoring device reports the track section as free.

[0008] A significant advantage of the method according to the invention is that it enables reliable ghost train detection even at high speeds of the rail vehicle and with a long signal processing time of the track section monitoring device, since the section between the track section and the rail vehicle is monitored for the minimum observation period provided according to the invention.

[0009] To ensure that the correct marking is always taken into account when checking for a ghost train on closely spaced tracks, it is considered advantageous if the markings are each provided with an identification symbol that identifies the marking or track section, and if the identification symbols are evaluated, at least when the camera signals detect two or more markings. The identification symbols can, for example, comprise or be formed by one- or two-dimensional codes such as QR codes.

[0010] It is advantageous if, in the ghost train detection, only the area between the rail vehicle and the marking or one of the markings assigned to the track section into which the rail vehicle will enter or which it has left is taken into account.

[0011] In a design variant considered particularly advantageous, the track section is provided with a first marking at one end and a second marking at its other, second end. A marking at each end is particularly advantageous when the track section is very long. For short track sections, a single marking may be sufficient under certain circumstances, provided it is visible both before entering and after leaving the track section.

[0012] A special orientation of the markings is not required; it is advantageous if they are recognizable regardless of the direction of travel or for every direction of travel.

[0013] In a variant of the method considered advantageous, it is provided that before the rail vehicle enters the first end of the track section reported as free and before passing the first marking, the track section and the area between the first marking and the rail vehicle are reported as free of ghost trains if, for the minimum observation period, both the camera signals indicate the area between the rail vehicle and the first marking as unoccupied and the track section monitoring device reports the track section as free.

[0014] In a further variant of the method which is regarded as advantageous, it is provided that after leaving the track section and after passing the second marking, the track section and the area between the second marking and the rail vehicle are reported as free of ghost trains if both the camera signals indicate the area between the rail vehicle and the second marking as unoccupied for the minimum observation period and the track section monitoring device reports the track section as free - at least upon expiry of the minimum observation period.

[0015] The first marking is preferably provided with a first identification symbol and the second marking with a second identification symbol.

[0016] In the case of marking with identification signs, it is advantageous if, before the rail vehicle enters the first end of the track section reported as free and before passing the first marking, which is recognized as such based on an evaluation of the first identification sign, the track section and the area between the first marking and the rail vehicle are reported as free of ghost trains, if for the specified minimum observation period both the camera signals indicate the area between the rail vehicle and the first marking as unoccupied and the track section monitoring device reports the track section as free.

[0017] In the case of marking with identification signs, it is also advantageous if, after leaving the track section and after passing the second marking, the track section and the area between the second marking, which is recognized as such based on an evaluation of the second identification sign, and the rail vehicle are reported as free of ghost trains, if both the camera signals indicate the area between the rail vehicle and the second marking as unoccupied for the minimum observation period and the track section monitoring device reports the track section as free at least when the minimum observation period has elapsed.

[0018] The camera, or at least one of the cameras, can be a trackside camera that performs trackside monitoring. However, it is considered particularly advantageous if the camera, or at least one of the cameras, is mounted on the rail vehicle and the track monitoring is also performed at least on the vehicle side. In other words, it is advantageous if the area between the rail vehicle and the marking is also monitored with at least one camera mounted on the rail vehicle.

[0019] In an advantageous development of the method, it is provided that the track section is provided with a first marking at a first end and with a second marking at its other second end, at least one front camera is mounted in a front section of the rail vehicle as seen in the direction of travel and is optically directed at least forwards, at least one rear camera is mounted in a rear section of the rail vehicle as seen in the direction of travel and is optically directed at least backwards,Before the rail vehicle enters the track section, the area between the rail vehicle and the first marking is monitored at least with the at least one front camera and a ghost train check is carried out with regard to any ghost train traveling ahead, and after leaving the track section, the area between the rail vehicle and the second marking is monitored at least with the at least one rear camera and a ghost train check is carried out with regard to any ghost train traveling behind.

[0020] The markings do not necessarily have to be located within the track section or exactly at the other end, but the distance between each of the markings and the assigned track section should not be greater than the shortest relevant train length of conceivable ghost trains that may be present on the track system.

[0021] As already mentioned, it is advantageous if the markings are recognizable regardless of the direction of travel or for every direction of travel; this makes it possible for the above-mentioned first marking to be used as the second marking in the sense of the above explanations when leaving the track section and for the second marking to be used as the first marking when entering the track section.

[0022] The invention further relates to a ghost train detection device.

[0023] According to the invention, an image processing device is provided which is designed to evaluate camera signals from at least one camera before a rail vehicle enters a track section reported as free by a track section monitoring device or after leaving the track section with regard to the section between the rail vehicle and an optically recognizable marking attached in the track section or at one end of the track section and to report the area between the marking and the rail vehicle as free if the camera signals indicate the area between the rail vehicle and the marking as unoccupied, and otherwise to report it as occupied by means of a train detection signal.

[0024] In addition, the ghost train detection device comprises a signal processing device which is designed in such a way that it observes a status signal of the track section monitoring device indicating the occupancy status of the track section for a predetermined minimum observation period which is at least as long as the signal processing time of the track section monitoring device and carries out ghost train detection on the basis of both the output signal of the image processing device, i.e. a train detection signal if present, and the status signal of the track section monitoring device.

[0025] With regard to the advantages of the ghost train detection device according to the invention and its advantageous embodiments, reference is made to the above statements in connection with the method according to the invention and its advantageous embodiments.

[0026] It is advantageous if the ghost train detection device is designed to carry out the ghost train detection methods described above.

[0027] It is particularly advantageous if the signal processing device is designed in such a way that it reports the track section and the area between the rail vehicle and the marking as free of ghost trains if the image processing device shows the area between the rail vehicle and the marking as unoccupied and the track section monitoring device reports the track section as free for the specified minimum observation period.

[0028] It is also advantageous if the signal processing device is designed in such a way that it reports the track section and the area between the rail vehicle and a marking already passed in the direction of travel as free of ghost trains if the image processing device shows the area between the rail vehicle and the marking as unoccupied for the minimum observation period and the track section monitoring device reports the track section as free at least when the minimum observation period has elapsed.

[0029] The invention also relates to a rail vehicle. According to the invention, the rail vehicle comprises at least one camera and a ghost train detection device connected to the camera, as described above.

[0030] With regard to the advantages of the rail vehicle according to the invention and its advantageous embodiments, reference is made to the above statements in connection with the method according to the invention and its advantageous embodiments.

[0031] The invention is explained in more detail below using exemplary embodiments; by way of example,

[0032] Figure 1 shows an example of a railway track system, which is used to explain the task of ghost train detection,

[0033] Fig. 2-3 shows an exemplary embodiment of a rail vehicle according to the invention, which is equipped with an exemplary embodiment of a ghost train detection device according to the invention, during its travel towards a track section equipped with a track section monitoring device and two markings,

[0034] Fig. 4-5 Examples of ghost train detection devices according to the invention,

[0035] Figure 6 shows the rail vehicle according to Figures 2 and 3 after leaving the track section,

[0036] Figure 7 shows the rail vehicle according to Figures 2 and 3 during its travel towards a track section equipped with a single marking, and

[0037] Figure 8 shows the rail vehicle according to Figures 2 and 3 during its travel towards a section of track provided with markings bearing identification symbols.

[0038] For the sake of clarity, the same reference symbols are used in the figures for identical or comparable components.

[0039] Figure 1 shows a railway track system 10, of which a track section 20 is shown in more detail in Figure 1. The track section 20 is spatially delimited by a first end 21, which is on the left in Figure 1, and a second end 22, which is on the right in Figure 1.

[0040] A first axle counter 31 is arranged in the area of ​​the first end 21 of the track section 20, and a second axle counter 32 is arranged at the second end 22 of the track section 20. The two axle counters 31 and 32 are connected to a counting device 33, which evaluates the counting results of the two axle counters 31 and 32 and, on the basis of the evaluation results, determines the occupancy status of the track section 20. A status signal ZS indicating the respective occupancy status is output by the counting device 33. The status signal ZS therefore indicates whether the track section 20 is occupied by one or more rail vehicles or is free of vehicles. The two axle counters 31 and 32 and the counting device 33 form a track section monitoring device 30 of the railway track system 10.

[0041] The counting device 33 and thus the track section monitoring device 30 are connected to a trackside communication device 40, which can transmit the status signal ZS of the counting device 33 via radio or other means to rail vehicles traveling on the railway track system 10, for example to a rail vehicle identified by reference symbol 50 in Figure 1. In the illustration according to Figure 1, the rail vehicle 50 travels along a direction of travel F toward the track section 20.

[0042] The trackside communication device 40 can, for example, form part of a signal box or a control center or the like.

[0043] Based on the status signal ZS transmitted by the trackside communication device 40, the rail vehicle 50 can, in principle, determine on its own or without any further external information whether a ghost train 60 is located in front of it in the direction of travel F as soon as it approaches the track section reported as free by the track section monitoring device 30. The term "ghost train 60" is understood here to mean a rail vehicle whose existence on the track system 10 is unknown to the control center or signal box and of which the rail vehicle 50 therefore has no knowledge.

[0044] Such a ghost train detection can be based solely on the observation of the status signal ZS, since the preceding ghost train 60 would cause the status signal ZS to change from "free" to "occupied" before the rail vehicle 50 itself enters the track section 20 and triggers the signal change. However, it is problematic that the track section monitoring device 30 requires a certain signal processing time Tv to generate the status signal ZS and output it. Furthermore, there may be a further delay in the transmission of the status signal ZS from the track section monitoring device 30 to the rail vehicle 50, for example, due to a delay Tu caused by the trackside communication device 40. Overall, a total delay time Tg is to be expected, which is composed, for example, of Tv and Tu according to

[0045] Tg = Tv + Tu

[0046] The delay Tu is usually significantly smaller than the signal processing time Tv, so that at least approximately the following applies:

[0047] Tg ~ Tv

[0048] The rail vehicle 50 can therefore only reliably detect a ghost train 60 traveling ahead based on a signal change of the status signal ZS if it approaches track section 20 very slowly, namely so slowly that the status signal ZS changes from a clear signal to an occupied signal before the rail vehicle 50 itself enters track section 20 and triggers a signal change. The maximum speed that the rail vehicle 50 may have for a ghost train detection shortly before entering track section 20 is calculated as follows:

[0049] V = Lr / Tg where V is the speed of the rail vehicle 50, Lr is the shortest possible relevant train length of the ghost train 60 and Tg is the total delay time that elapses between the entry of the ghost train 60 into the track section 20 and the receipt of the corresponding signal change of the status signal ZS in the rail vehicle 50. The relevant train length Lr results from the total train length Lg of the ghost train 60 less the front overhang (when the ghost train 60 enters the track section 20) between the front end of the ghost train 60 and the position of the frontmost axle of the ghost train 60.

[0050] Assuming a shortest relevant train length Lr of, for example, 8 meters and a total deceleration time Tg of, for example, 2.5 seconds, the speed V of the rail vehicle 50 before entering the track section 20 is limited to a relatively low value of approximately V = 12 km / h, provided that the rail vehicle 50 itself wishes to carry out ghost train detection solely on the basis of the status signal ZS. The rail vehicle 50 must maintain this low speed V on a section whose length corresponds to the relevant train length Lr of the ghost train 60 before the start of the track section 20.

[0051] In order to enable the rail vehicle 50 to carry out ghost train detection even at higher speeds, the rail vehicle 50 according to Figure 2 is additionally equipped with at least one camera, preferably with a front camera 81 directed forwards as seen in the direction of travel F for detecting a ghost train 60 traveling ahead and a rear camera 82 directed rearwards as seen in the direction of travel F for detecting a ghost train traveling behind. The two cameras 81 and 82 are connected to an on-board ghost train detection device 90 which evaluates the camera signals from the two cameras 81 and 82 and, taking into account the respective status signal ZS or signal changes in the status signal ZS, concludes the presence or absence of a ghost train 60.Furthermore, the track section 20 is equipped with a first marking 71, which is arranged in the region of the first end 21 of the track section 20, and a second marking 72, which is arranged in the region of the second end 22 of the track section 20. The two markings 71 and 72 make it easy to visually identify the beginning and end of the track section 20.

[0052] The ghost train detection device 90 is preferably designed such that it monitors the front area of ​​the rail vehicle 50 with the front camera 81 while traveling in the direction of the track section 20. If it detects the first marking 71, it can check the area B between the first marking 71 and the rail vehicle 50 itself for the presence of another vehicle or a ghost train 60 and generate an output signal AS on the output side, which may indicate the existence of the ghost train 60, as shown by way of example in Figure 2.

[0053] Otherwise, if the area B between the first marking 71 and the rail vehicle 50 is free, it can conclude that there is no ghost train 60 in the area B. If the status signal ZS of the track section monitoring device 30 now also indicates that the track section 20 is also free of vehicles, the ghost train detection device 90 cannot yet conclude from the status signal ZS and the camera signals of the front camera 81 that the ghost train 60 is actually missing and cannot yet make a final determination in this regard.

[0054] The problem is again the signal processing time Tv of the track section monitoring device 30 already mentioned above, as well as - if present to a relevant extent - the delay times of other devices such as the trackside communication device 40, which lead to a delayed transmission of the status signal ZS from the track section 20 to the rail vehicle 50. To ensure that the ghost train detection device 90 does not miss a ghost train 60, it will extend the evaluation of the camera signals of the front camera 81 to a predetermined minimum observation period Tmin, which is at least as long as the signal processing time Tv of the track section monitoring device 90 and preferably also takes into account any further delays Ts caused by other devices, provided the latter are not negligibly small. The following therefore applies:

[0055] Tmin > Tv + Ts » Tv

[0056] If the other delays Ts are small and virtually negligible, then, with a view to a safety margin, it can be provided, for example, that the minimum observation period Tmin is calculated from the signal processing time Tv of the track section monitoring device 90 according to

[0057] Tmin = ( 1+k) * Tv where k denotes a margin value of, for example, between 0 . 1 and 0 . 5 .

[0058] If the ghost train detection device 90 of the rail vehicle 50 now determines that the front area B between the rail vehicle 50 and the first marking 71 is free of ghost trains for the predetermined minimum observation period Tmin and if no change in the status signal ZS from "clear signal" to "occupied signal" has occurred within this minimum observation period Tmin, it can conclude that there is no ghost train 60 ahead of its own rail vehicle 50 and it can accordingly output a corresponding output signal AS which indicates the absence of a ghost train 60.

[0059] If, on the other hand, it determines that within the minimum observation period Tmin there is a signal change in the status signal ZS from a clear message to an occupied message, it will conclude that although the front area B between the own rail vehicle 50 and the first marking 71 is free of ghost trains, a ghost train 60 traveling ahead had already entered the track section 20 before the start of the camera monitoring or before the start of the minimum observation period Tmin, so that it could not be detected by the front camera 81 (cf. Figure 3). Accordingly, the ghost train detection device 90 will output a corresponding output signal AS which indicates the presence of a ghost train 60.

[0060] Assuming, for example, that the visibility range SW of the front camera 81 is eighty meters, the rail vehicle 50 can theoretically travel at a speed V according to

[0061] V = SW / Tg = 120 km / h approach track section 20 without losing the possibility of ghost train detection.

[0062] In summary, the described ghost train detection device 90 according to Figures 1 to 3 makes it possible to carry out reliable ghost train detection even at relatively high travel speeds by evaluating the status signal ZS of the track section monitoring device 30 and by additionally evaluating the camera signals of the cameras 81, since the signal processing time Tv of the track section monitoring device 30 or the total delay time Tg dependent thereon is taken into account by providing the described minimum observation period Tmin.

[0063] Figure 4 shows an exemplary embodiment of a ghost train detection device 90 which can be used in the rail vehicle 50 according to Figures 2 and 3.

[0064] The ghost train detection device 90 according to Figure 4 comprises an image processing device 91 which processes camera signals KS from the two cameras 81 and 82 of the rail vehicle 50, and a signal processing device 92 arranged downstream of the image processing device 91.

[0065] The operation of the image processing device 91 and the downstream signal processing device 92 will be explained below by way of example for the travel of the rail vehicle 50 in the direction of the track section 20 (see Figures 2 and 3), whereby it is assumed that the status signal ZS indicates the track section 20 as free:

[0066] The image processing device 91 generates a mark detection signal MZ on the output side as soon as the first mark 71 is detected.

[0067] If the image processing device 91 also determines that there is a ghost train 60 in the area B between the rail vehicle 50 and the first marking 71 (see Figure 2), it also generates a train detection signal ZES.

[0068] The marking detection signal MZ and, if applicable, the train detection signal ZES are forwarded to the signal processing device 92 which, when the marking detection signal MZ and the train detection signal ZES are present, generates an output signal AS which indicates the presence of the ghost train 60 in the area B, i.e. between the rail vehicle 50 and the first marking 71.

[0069] If the signal processing device 92 only has the marking detection signal MZ but no train detection signal ZES present on the input side, the signal processing device 92 monitors the status signal ZS of the track section monitoring device 30 for a predetermined minimum observation period Tmin, which is at least as long as the signal processing time Tv of the track section monitoring device 30. The minimum observation period Tmin is started with the generation or with the presence of the marking detection signal MZ.

[0070] If for the specified minimum observation period Tmin both the marking detection signal MZ is present and the status signal ZS indicates the track section 20 as continuously unoccupied, the signal processing device 92 reports the track section 20 as ghost train-free with the output signal AS.

[0071] However, if within the minimum observation period Tmin a signal change of the status signal ZS from "free" to "occupied" takes place, the signal processing device 92 concludes that the ghost train 60 had already entered the track section 20 before the start of the minimum observation period Tmin or before the start of observation (i.e. before the presence of the marking detection signal MZ), as shown in Figure 3. Accordingly, the signal processing device 92 reports the detected ghost train 60 traveling ahead and generates a corresponding output signal AS on the output side.

[0072] By waiting for the minimum observation period Tmin, the signal processing device 92 ensures that the signal processing time Tv of the track section monitoring device 30 cannot conceal a ghost train 60 traveling ahead.

[0073] Figure 5 shows a further exemplary embodiment of a ghost train detection device 90 that can be used in the rail vehicle 50 according to Figures 2 and 3. The ghost train detection device 90 according to Figure 5 comprises a computing device 910 and a memory 920.

[0074] An image processing module 91a is stored in the memory 920, which, when executed by the computing device 910, forms an image processing device 91, as has been explained by way of example in connection with Figure 4.

[0075] In addition, a signal processing module 92a is stored in the memory 920, which, when executed by the computing device 910, forms a signal processing device 92, as has been explained in connection with Figure 4.

[0076] The computing device 910 and the memory 920 can form a self-contained ghost train detection device 90 in the rail vehicle 50. Alternatively, it can be provided that the image processing module 91a and the signal processing module 92a are stored in a memory of a vehicle control unit, whose computing device, when the two modules 91a and 92a are executed, carries out the ghost train detection as an additional function, as explained above by way of example.

[0077] Figure 6 shows an example of the operation of the ghost train detection device 90 according to Figures 2 to 5 after the rail vehicle 50 has moved out of the track section 20 for the purpose of detecting a ghost train 60 following behind.

[0078] After exiting track section 20, the area B between the second marking 72 and the rail vehicle 50 is monitored with the aid of the rear camera 82. As soon as the second marking 72 has been detected using the camera signals KS of the rear camera 82, the ghost train detection device 90 monitors the area between the second marking 72 and the rail vehicle 50 for the minimum observation period Tmin already explained. In addition, the ghost train detection device 90 monitors the status signal ZS of the track section monitoring device 30.

[0079] If, for the predetermined minimum observation period Tmin, the camera signals KS of the rear camera 82 indicate the section B between the rail vehicle 50 and the second marking 72 as unoccupied and the track section monitoring device 30 reports the track section 20 as free by means of the status signal ZS at least upon expiry of the minimum observation period, the ghost train detection device 90 concludes that the track section 20 and the area between the second marking 72 and the rail vehicle 50 is free of ghost trains and generates a corresponding output signal AS.

[0080] If, within the predetermined minimum observation period Tmin, either the camera signals KS of the rear camera 82 indicate a ghost train 60 or the track section monitoring device 30 reports the track section 20 as continuously occupied by means of the status signal ZS, the ghost train detection device 90 concludes that a ghost train 60 is following the rail vehicle 50 and generates a corresponding output signal AS.

[0081] Figure 7 shows a track section 20 equipped with a single marker 70. Ghost train detection is also possible with just a single marker 70, analogous to the above embodiments with two markers 71 and 72; only, both upon entering track section 20 and upon exiting track section 20, the observation is carried out using the same marker 70. Otherwise, the above explanations apply accordingly in connection with Figures 1 to 6.

[0082] In order to ensure that the correct markings are always taken into account when tracks are closely adjacent, it is considered advantageous if the markings are each provided with an identification symbol II or I2 that identifies the respective marking or the respective track section 20, as shown by way of example in Figure 8. If recognized identification symbols or their markings do not match the markings of the next (before entering) or last (after exiting) track section 20, the corresponding markings are preferably ignored or not used for ghost train detection. The identification symbols II and I2 can advantageously be formed by QR codes or include such codes.

[0083] Finally, it should be mentioned that the features of all the embodiments described above can be combined with one another in any way to form further other embodiments of the invention.

[0084] All features of subclaims can also be combined individually with each of the subordinate claims, either individually or in any combination with one or other subclaims, in order to obtain further embodiments.

Claims

Patent claims 1. Method for detecting ghost trains in the context of the operation of a railway track system (10) , characterized in that - in the procedure a track section (20) is monitored for its occupancy status by a track section monitoring device (30) having a signal processing time (Tv) and is reported as free or occupied, - before a rail vehicle (50) enters the track section (20) reported as clear or after leaving the track section (20), the area (B) between the rail vehicle (50) and an optically recognizable marking (70, 71, 72) placed in the track section (20) or at one end (21, 22) of the track section (20) is monitored with at least one camera (81, 82) and - the track section (20) and the area (B) between the marker (70, 71, 72) and the rail vehicle (50) are reported as free of ghost trains if, for a specified minimum observation period which is at least as long as the signal processing time (Tv) of the track section monitoring device (30), camera signals (KS) of the camera (81, 82) indicate the area (B) between the rail vehicle (50) and the marker (70, 71, 72) as unoccupied, and at least at the end of the minimum observation period, the track section monitoring device (30) reports the track section (20) as free.

2. The method according to claim 1, characterized in that - the marking (71, 72) is provided with an identification mark (II, 12) identifying the marking (71, 72) or the track section (20) and - at least in the case that the camera signals (KS) detect two or more markings that are identification marks (II, 12) will be evaluated.

3. Method according to one of the preceding claims, characterized in that, in the ghost train detection, only the area between the rail vehicle (50) and the marking or one of the markings that is assigned to the track section (20) into which the rail vehicle (50) will enter or from which it has left is taken into consideration.

4. Method according to one of the preceding claims, characterized in that the track section (20) is equipped at a first end (21) with a first marking (71) and at its other second end (22) with a second marking (72).

5. Method according to claim 4, characterized in that, prior to the entry of the rail vehicle (50) at the first end (21) of the track section (20) reported as clear and prior to passing the first marking (71), the track section (20) and the area (B) between the first marking (71) and the rail vehicle (50) are reported as free of ghost trains if, for the minimum observation period, both the camera signals (KS) indicate the area (B) between the rail vehicle (50) and the first marking (71) as unoccupied and the track section monitoring device (30) reports the track section (20) as clear.

6. Method according to one of the preceding claims 4 to 5, characterized in that, after exiting the track section (20) and after passing the second marker (72), the track section (20) and the area (B) between the second marker (72) and the rail vehicle (50) are reported as free of ghost trains if, for the minimum observation period, both the camera signals (KS) indicate the area (B) between the rail vehicle (50) and the second marker (72) as unoccupied and the track section monitoring device (30) reports the track section (20) as clear at least when the minimum observation period has elapsed.

7. Method according to any one of the preceding claims 4 to 6, characterized in that the first marking (71) is provided with a first identification mark (II) and the second marking (72) is provided with a second identification mark (12).

8. Method according to claim 7, characterized in that, prior to the entry of the rail vehicle (50) at the first end (21) of the track section (20) reported as clear and prior to passing the first marking (71), which is recognized as such by an evaluation of the first identification mark (II), the track section (20) and the area (B) between the first marking (71) and the rail vehicle (50) are reported as free of ghost trains if, for the specified minimum observation period, both the camera signals (KS) indicate the area (B) between the rail vehicle (50) and the first marking (71) as unoccupied and the track section monitoring device (30) reports the track section (20) as clear.

9. Method according to one of the preceding claims 7 to 8, characterized in that, after exiting the track section (20) and after passing the second marking (72), the track section (20) and the area (B) between the second marking (72), which is recognized as such by an evaluation of the second identification mark (12), and the rail vehicle (50) are reported as free of ghost trains if, for the minimum observation period, both the camera signals (KS) indicate the section between the rail vehicle (50) and the second marking (72) as unoccupied and the track section monitoring device (30) reports the track section (20) as free at least at the end of the minimum observation period.

10. Method according to any one of the preceding claims, characterized in that - the camera (81, 82) or at least one of the cameras is attached to the rail vehicle (50) and - the section between the rail vehicle (50) and the marking (70, 71, 72) is also monitored at least by the camera (81, 82) attached to the rail vehicle (50).

11. Method according to any one of the preceding claims, characterized in that - the track section (20) is equipped at a first end (21) with a first marker (71) and at its other second end (22) with a second marker (72), - at least one front camera (81) is installed in a front section of the rail vehicle (50) as seen in the direction of travel (F) and is optically oriented at least forwards, - at least one rear camera (82) is installed in a rear section of the rail vehicle (50) as seen in the direction of travel (F) and is optically directed at least to the rear, - before the rail vehicle (50) enters the track section (20) the area (B) between the rail vehicle (50) and the first marking (71) is monitored at least also by the at least one front camera (81) and - after exiting the track section (20) the area (B) between the rail vehicle (50) and the second marking (70, 71, 72) is also monitored by at least one rear camera (81).

12. Ghost train detection device (90) , characterized by - an image processing device (91) which is designed to process camera signals (CS) from at least one camera (81, 82) before a rail vehicle (50) enters a track section (20) reported as clear by a track section monitoring device (30) or after leaving the track section (20), to evaluate the area (B) between the rail vehicle (50) and an optically detectable marker (70, 71, 72) located in or at one end of the track section (20) and to report the area between the marker (70, 71, 72) and the rail vehicle (50) as clear if the camera signals (CS) indicate that the area (B) between the rail vehicle (50) and the marker (70, 71, 72) is unoccupied, and otherwise to report it as occupied, and - a signal processing device (92) which is designed such that it observes a status signal (ZS) of the track section monitoring device (30) indicating the occupancy status of the track section (20) for a specified minimum observation period which is at least as long as the signal processing time (Tv) of the track section monitoring device (30) and performs ghost train detection on the basis of both an occupancy message from the image processing device (91) and the status signal (ZS) of the track section monitoring device (30).

13. Ghost train detection device (90) according to claim 12, characterized in that the signal processing device (92) is configured such that it reports the track section (20) and the area (B) between the rail vehicle (50) and the marker (70, 71, 72) as free of ghost trains when the image processing device (91) indicates the area (B) between the rail vehicle (50) and the marker (70, 71, 72) as unoccupied and the track section monitoring device (30) reports the track section (20) as free for the specified minimum observation period.

14. Ghost train detection device (90) according to claim 12 or 13, characterized in that the signal processing device (92) is configured such that it reports the track section (20) and the area (B) between the rail vehicle (50) and a marking (70, 71, 72) already passed in the direction of travel as ghost train free, if for the minimum observation period the image processing device (91) displays the area (B) between the rail vehicle (50) and the marking (72) as unoccupied and the track section monitoring device (30) reports the track section (20) as free at least at the end of the minimum observation period.

15. Railway vehicle (50) characterized by the fact that the railway vehicle (50) comprises - at least one camera (81) and - a ghost train detection device (90) connected to the camera (81) according to one of the preceding claims 12 to 14.

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