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] The invention relates to a method for detecting ghost trains during the operation of a railway track system. A ghost train is understood here to be a rail vehicle whose existence on the track system is unknown from the trackside, i.e., from the control center or signal box side, and which is therefore also unknown to the rail vehicles known to operate on the railway track system.

[0002] Document EP 3 782 870 B1 discloses a method for detecting ghost trains.

[0003] The invention is based on the objective of providing a method for ghost train detection that enables simple ghost train detection by including a track section monitoring device.

[0004] This problem is solved according to the invention by a method with the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the dependent claims.

[0005] According to the invention, the method provides that a track section is monitored for occupancy by a track section monitoring device having a signal processing time and is reported as free or occupied; before a rail vehicle enters the track section reported as free or after it leaves the track section, the area between the rail vehicle and an optically recognizable marking located in the track section or at one end of the track section is monitored by at least one camera; and 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,The camera signals indicate that the area between the rail vehicle and the marking is unoccupied, and at least after the minimum observation period has elapsed, the track section monitoring device reports the track section as clear.

[0006] 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 long signal processing times 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 for in the invention.

[0007] To ensure that the correct marking is always considered when checking for the presence of a ghost train on closely adjacent tracks, it is considered advantageous if each marking is provided with an identification mark that identifies the marking or track section. This identification mark should be evaluated, at least when the camera signals detect two or more markings. The identification marks can, for example, include or be formed by one- or two-dimensional codes such as QR codes.

[0008] It is advantageous if, in the case of ghost train detection, only the area between the rail vehicle and the marking(s) that is assigned to the track section into which the rail vehicle will enter or from which it has left is taken into account.

[0009] In one particularly advantageous design variant, the track section is provided with a first marking at one end and a second marking at its other end. A marking at each end is especially beneficial when the track section is very long. For short track sections, a single marking may suffice if it is visible both before entering and after leaving the track section.

[0010] A specific orientation of the markings is not required; however, it is advantageous if they are recognizable regardless of the direction of travel or for every direction of travel.

[0011] In a variant of the procedure considered advantageous, it is provided that before the rail vehicle enters the first end of the track section reported as clear 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 that the area between the rail vehicle and the first marking is unoccupied and the track section monitoring device also reports the track section as clear.

[0012] In another variant of the procedure, which is considered advantageous, it is provided that after exiting the track section and 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, for the minimum observation period, the camera signals indicate that the area between the rail vehicle and the second marking is unoccupied and the track section monitoring device reports the track section as clear, at least after the minimum observation period has expired.

[0013] The first marking is preferably provided with a first identification mark and the second marking with a second identification mark.

[0014] In the case of a marking with identification marks, it is advantageous if, before the rail vehicle enters the first end of the track section reported as clear and before passing the first marking, which is recognized as such by an evaluation of the first identification mark, the track section and the area between the first marking and the rail vehicle are reported as free of ghost trains, provided that 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 clear.

[0015] In the case of a marking with identification marks, it is also advantageous if, after exiting the track section and passing the second marking, the track section and the area between the second marking, which is recognized as such by an evaluation of the second identification mark, and the rail vehicle are reported as free of ghost trains, if both for the minimum observation period the camera signals indicate the area between the rail vehicle and the second marking as unoccupied and the track section monitoring device reports the track section as free at least at the end of the minimum observation period.

[0016] The camera, or at least one of the cameras, can be a trackside camera used for monitoring the track. 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 carried out on the vehicle side. In other words, it is advantageous if the area between the rail vehicle and the marking is also monitored by a camera mounted on the rail vehicle.

[0017] In an advantageous further development of the method, it is provided that the track section is equipped with a first marking at a first end and with a second marking at its other second end, that 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 oriented at least also forwards, and that 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 oriented at least also backwards.Before the rail vehicle enters the track section, the area between the rail vehicle and the first marker is monitored by at least one front camera, and a ghost train check is performed to detect any ghost trains that may be approaching. After the rail vehicle leaves the track section, the area between the rail vehicle and the second marker is monitored by at least one rear camera, and a ghost train check is performed to detect any ghost trains that may be following behind. The markers do not necessarily have to be located within the track section or exactly at opposite ends; however, the distance between each marker and the corresponding track section should not exceed the shortest relevant train length of any conceivable ghost trains that might be present on the track.

[0018] 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 first marking mentioned above to be used as the second marking when exiting the track section, in accordance with the explanations above, and for the second marking to be used as the first marking when entering the track section.

[0019] The invention further relates to a ghost train detection device according to claim 12. According to the invention, an image processing device is provided which is configured to evaluate camera signals from at least one camera before a rail vehicle enters a track section reported as clear by a track section monitoring device or after it leaves the track section with respect to the section between the rail vehicle and an optically detectable marking located in the track section or at an end of the track section, and to report the area between the marking and the rail vehicle as clear if the camera signals indicate that the area between the rail vehicle and the marking is unoccupied, and otherwise to report it as occupied by means of a train detection signal.

[0020] Furthermore, the ghost train detection device includes a signal processing device designed to monitor a status signal of the track section monitoring device indicating the occupancy 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 to perform ghost train detection based on 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.

[0021] Regarding 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.

[0022] It is advantageous if the ghost train detection device is designed to carry out the ghost train detection procedures described above.

[0023] 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 indicates the area between the rail vehicle and the marking as unoccupied, and if the track section monitoring device reports the track section as clear for the specified minimum observation period.

[0024] 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 for the minimum observation period the image processing device displays the area between the rail vehicle and the marking as unoccupied and the track section monitoring device reports the track section as free at least when the minimum observation period has elapsed.

[0025] 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.

[0026] Regarding 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.

[0027] The invention is explained in more detail below with reference to exemplary embodiments; these show, by way of example, Figure 1 shows an embodiment of a railway track system, which illustrates the task of ghost train detection; Figures 2-3 show an embodiment of a rail vehicle according to the invention, which is equipped with an embodiment of a ghost train detection device according to the invention, as it travels towards a track section equipped with a track section monitoring device and two markings; Figures 4-5 show embodiments of ghost train detection devices according to the invention; Figure 6 shows the rail vehicle according to the Figures 2 and3 After leaving the track section, Figure 7, the rail vehicle according to the Figures 2 and 3 during its journey towards a track section equipped with a single marking, and Figure 8 the rail vehicle according to the Figures 2 and 3 during its journey towards a section of track equipped with markings bearing identification symbols.

[0028] For the sake of clarity, the same reference symbols are used in the figures for identical or comparable components.

[0029] The Figure 1 shows a railway track system 10, of which in the Figure 1 A track section 20 is shown in more detail. Track section 20 is defined by a first, in the Figure 1 left end 21 and a second one, in the Figure 1 right end 22 spatially limited.

[0030] At the first end 21 of track section 20, a first axle counter 31 is arranged, and at the second end 22 of track section 20, a second axle counter 32 is arranged. 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 determines the occupancy status of track section 20 based on these results. A status signal ZS indicating the respective occupancy status is output by the counting device 33. The status signal ZS thus indicates whether track section 20 is occupied by one or more rail vehicles or is clear 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.

[0031] The counting device 33, and thus the track section monitoring device 30, are connected to a trackside communication device 40, which transmits 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 [vehicle / station] in the Figure 1 Rail vehicle marked with reference number 50, can be transmitted. Rail vehicle 50 is depicted according to Figure 1 along a direction of travel F towards track section 20.

[0032] The trackside communication device 40 can, for example, form part of a signal box or a control center or the like.

[0033] Based on the status signal ZS transmitted by the trackside communication device 40, the rail vehicle 50 can, in principle, determine on its own, without further external information, whether a ghost train 60 is located ahead of it in the direction of travel F, as soon as it approaches the track section reported as clear 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 is therefore also unaware.

[0034] Such ghost train detection can be based solely on the observation of the status signal ZS, since the preceding ghost train 60 would cause a signal change of the status signal ZS from "free" to "occupied" before the rail vehicle 50 itself enters track section 20 and triggers the signal change.

[0035] However, a problem arises because the track section monitoring device 30 requires a certain signal processing time Tv to generate and output the status signal ZS. Furthermore, there may be an additional 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. Therefore, a total delay time Tg must be expected, which is composed, for example, of Tv and Tu according to... Tg = Tv + Tu

[0036] The delay Tu is usually significantly smaller than the signal processing time Tv, so at least approximately: Tg ≈ Tv

[0037] The rail vehicle 50 can therefore reliably detect a ghost train 60 traveling ahead of it based on a signal change of the status signal ZS only if it approaches track section 20 very slowly, specifically so slowly that the status signal ZS changes from a clear indication to an occupancy indication 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 to detect a ghost train shortly before entering track section 20 is calculated as follows: V = Lr / Tg where V is the speed of rail vehicle 50, Lr is the shortest conceivable relevant train length of the ghost train 60, and Tg is the total delay time that elapses between the ghost train 60 entering track section 20 and the rail vehicle 50 receiving the corresponding signal change of the status signal ZS. The relevant train length Lr is calculated by subtracting the front overhang (when the ghost train 60 enters track section 20) between the front end of the ghost train 60 and the position of its foremost axle from the total train length Lg of the ghost train 60.

[0038] Assuming a shortest relevant train length Lr of, for example, 8 meters and a total delay time Tg of, for example, 2.5 seconds, the speed V of rail vehicle 50 before entering track section 20 will be limited to a relatively low value of approximately V = 12 km / h, provided that rail vehicle 50 is to perform ghost train detection solely based on the status signal ZS. Rail vehicle 50 must maintain this low speed V on a section of track whose length corresponds to the relevant train length Lr of the ghost train 60 before entering track section 20.

[0039] In order to enable the rail vehicle 50 to perform ghost train detection even at higher speeds, the rail vehicle 50 is designed according to Figure 2The vehicle is additionally equipped with at least one camera, preferably a forward-facing camera 81 (as viewed in the direction of travel F) for detecting a ghost train 60 that is traveling ahead, and a rear-facing camera 82 (as viewed in the direction of travel F) for detecting a ghost train traveling behind. The two cameras 81 and 82 are connected to a vehicle-integrated 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 changes in the status signal ZS, concludes whether a ghost train 60 is present or absent.

[0040] Furthermore, track section 20 is equipped with a first marker 71, located in the area of ​​the first end 21 of track section 20, and a second marker 72, located in the area of ​​the second end 22 of track section 20. The two markers 71 and 72 make it easy to visually identify the beginning and end of track section 20.

[0041] The ghost train detection device 90 is preferably designed such that, while traveling towards track section 20, it monitors the front area of ​​the rail vehicle 50 with the front camera 81. If it detects the first marker 71, it can check the area B between the first marker 71 and its own rail vehicle 50 for the presence of another vehicle or a ghost train 60 and generate an output signal AS, which may indicate the existence of the ghost train 60, as described in the Figure 2This is shown as an example.

[0042] Otherwise, if area B between the first marker 71 and the rail vehicle 50 is clear, it can conclude that there is no ghost train 60 in area B. If the status signal ZS of the track section monitoring device 30 also indicates that 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 absent, and therefore cannot yet make a final determination in this regard.

[0043] The problematic aspect is again the signal processing time Tv of the track section monitoring device 30, which has already been 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 track section 20 to the rail vehicle 50.

[0044] 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 from 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 these are not negligibly small. Therefore, the following applies: Tmin > Tv + Ts ≈ Tv

[0045] If the other delays Ts are small and virtually negligible, it may be provided, for example, that the minimum observation period Tmin is calculated based on the signal processing time Tv of the track section monitoring device 90, in accordance with a safety margin. Tmin = 1 + k * Tv where k denotes a margin value of, for example, between 0.1 and 0.5.

[0046] If the ghost train detection device 90 of the rail vehicle 50 now determines that for the specified minimum observation period Tmin the front area B between the rail vehicle 50 and the first marker 71 is free of ghost trains and that within this minimum observation period Tmin no change of the status signal ZS from "free" to "occupied" has occurred, it can conclude that no ghost train 60 is ahead of its own rail vehicle 50, and it can accordingly output a corresponding output signal AS indicating the absence of a ghost train 60.

[0047] If, however, it determines that within the minimum observation period Tmin a signal change of the status signal ZS from a free indication to an occupied indication takes place, it will conclude that although the front area B between its own rail vehicle 50 and the first marker 71 is free of ghost trains, a ghost train 60 had already entered track section 20 before the start of 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, indicating the presence of a ghost train 60.

[0048] Assuming, for example, that the visibility range SW of the front camera is 81 eighty meters, the rail vehicle can theoretically travel at a speed V according to V = SW / Tg = 120 km / h approach track section 20 without losing the possibility of ghost train detection.

[0049] In summary, the described ghost train detection device 90 enables, according to the Figures 1 to 3 Thus, by evaluating the status signal ZS of the track section monitoring device 30 and by additionally evaluating the camera signals of the cameras 81, a reliable ghost train detection can be carried out even at relatively high speeds, since the signal processing time Tv of the track section monitoring device 30 or the total delay time Tg dependent on it is taken into account by providing the described minimum observation period Tmin.

[0050] The Figure 4 shows an embodiment of a ghost train detection device 90, which is installed on the rail vehicle 50 according to the Figures 2 and 3 can be used.

[0051] The ghost train detection device 90 according to Figure 4 comprises an image processing unit 91, which processes camera signals KS from the two cameras 81 and 82 of the rail vehicle 50, and a signal processing unit 92 subordinate to the image processing unit 91.

[0052] The operation of the image processing unit 91 and the subordinate signal processing unit 92 will below be illustrated by way of example for the journey of the rail vehicle 50 in the direction of track section 20 (see Figures 2 and 3 ) explained, assuming that the status signal ZS indicates track section 20 as clear: The image processing device 91 generates an output marker recognition signal MZ as soon as the first marker 71 is detected.

[0053] Furthermore, if the image processing device 91 detects that a ghost train 60 is located in area B between the rail vehicle 50 and the first marker 71 (see Figure 2), it also generates a train detection signal ZES.

[0054] The marker recognition signal MZ and, if applicable, the train recognition signal ZES are forwarded to the signal processing unit 92, which, if the marker recognition signal MZ and the train recognition signal ZES are present, generates an output signal AS that indicates the presence of the ghost train 60 in area B, i.e. between rail vehicle 50 and the first marker 71.

[0055] If the signal processing unit 92 receives only the marker detection signal MZ at the input side, but no train detection signal ZES, the signal processing unit 92 monitors the status signal ZS of the track section monitoring unit 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 unit 30. The minimum observation period Tmin starts with the generation or availability of the marker detection signal MZ.

[0056] If, for the specified minimum observation period Tmin, both the marker recognition signal MZ is present and the status signal ZS indicates that track section 20 is continuously unoccupied, the signal processing unit 92 reports track section 20 as free of ghost trains with the output signal AS.

[0057] However, if within the minimum observation period Tmin a signal change of the status signal ZS from "free" to "occupied" occurs, the signal processing unit 92 concludes that the ghost train 60 had already entered 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 marker recognition signal MZ), as the Figure 3 This shows that the signal processing unit 92 reports the detected preceding ghost train 60 and generates a corresponding output signal AS.

[0058] By waiting for the minimum observation period Tmin, the signal processing unit 92 ensures that the signal processing time Tv of the track section monitoring unit 30 cannot conceal a ghost train 60 ahead.

[0059] The Figure 5shows a further embodiment of a ghost train detection device 90, which is installed on the rail vehicle 50 according to the Figures 2 and 3 can be used. The ghost train detection device 90 according to Figure 5 It includes a computing unit 910 and a storage unit 920.

[0060] Memory 920 contains an image processing module 91a, which, when executed by the computing unit 910, forms an image processing unit 91, as exemplified in connection with the Figure 4 has been explained.

[0061] Furthermore, a signal processing module 92a is stored in memory 920, which, when executed by the computing unit 910, forms a signal processing unit 92, as described in connection with the Figure 4 has been explained.

[0062] The computing unit 910 and the memory 920 can form a self-contained ghost train detection system 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 unit, when both modules 91a and 92a are implemented, performs ghost train detection as an additional function, as described above.

[0063] The Figure 6 This exemplifies the operation of the ghost train detection device 90 according to the Figures 2 to 5 after the rail vehicle 50 has left track section 20 in order to detect a ghost train 60 following behind it.

[0064] After exiting track section 20, the area B between the second marker 72 and the rail vehicle 50 is monitored using the rear camera 82. As soon as the second marker 72 has been detected by the camera signals KS of the rear camera 82, the ghost train detection device 90 observes the area between the second marker 72 and the rail vehicle 50 for the previously explained minimum observation period Tmin. In addition, the ghost train detection device 90 monitors the status signal ZS of the track section monitoring device 30.

[0065] If, for the specified minimum observation period Tmin, the camera signals KS of the rear camera 82 indicate that section B between the rail vehicle 50 and the second marker 72 is unoccupied, and the track section monitoring device 30 reports track section 20 as clear by means of the status signal ZS at least at the end of the minimum observation period, the ghost train detection device 90 concludes that track section 20 and the area between the second marker 72 and the rail vehicle 50 are free of ghost trains and generates a corresponding output signal AS.

[0066] If, within the specified 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.

[0067] The Figure 7 Figure 1 shows a track section 20 equipped with a single marker 70. Ghost train detection is also possible with only a single marker 70, analogous to the explanations above with two markers 71 and 72; the only difference is that the observation is carried out using the same marker 70 both when entering and exiting track section 20. Otherwise, the explanations above apply in connection with the Figures 1 to 6accordingly.

[0068] 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 mark I1 or I2 identifying the respective marking or track section 20, as exemplified by the Figure 8 This shows that if recognized identification marks 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 marks I1 and I2 can advantageously be formed by or include QR codes.

Claims

1. Method for ghost train detection as part of operation of a railway track installation (10), wherein - during the method a track section (20) with a track section monitoring facility (30) that has a signal processing time (Tv) is monitored in terms of its occupancy state and is reported as free or occupied, - before a rail vehicle (50) travels into the track section (20) reported as free, or after travelling out from the track section (20), the region (B) between the rail vehicle (50) and an optically detectable marking (70, 71, 72) attached in the track section (20) or at an end (21, 22) of the track section (20) is monitored using 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 free of ghost trains if both camera signals (KS) of the camera (81, 82) indicate that the region (B) between the rail vehicle (50) and the marking (70, 71, 72) is unoccupied, for a predefined minimum observation time period, which is at least as large as the signal processing time (Tv) of the track section monitoring facility (30), and the track section monitoring facility (30) reports that the track section (20) is free at least when the minimum observation time period expires.

2. Method according to claim 1, wherein - the marking (71, 72) is provided with an identification symbol (I1, I2) which identifies the marking (71, 72) or the track section (20) and - at least in the event that the camera signals (KS) capture two or more markings, the identification symbols (I1, I2) are evaluated.

3. Method according to one of the preceding claims, wherein the ghost train detection exclusively takes into consideration the region between the rail vehicle (50) and the or one of the markings, which is assigned to the track section (20) into which the rail vehicle (50) will travel or from which it has departed.

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

5. Method according to claim 4, wherein before the rail vehicle (50) travels in at the first end (21) of the track section (20) reported as free and before passing the first marking (71), the track section (20) and the region (B) between the first marking (71) and the rail vehicle (50) are reported as free of ghost trains if, for the minimum observation time period, both the camera signals (KS) indicate that the region (B) between the rail vehicle (50) and the first marking (71) is unoccupied, and the track section monitoring facility (30) reports that the track section (20) is free.

6. Method according to one of the preceding claims 4 to 5, wherein after travelling out from the track section (20) and after passing the second marking (72), the track section (20) and the region (B) between the second marking (72) and the rail vehicle (50) are reported as free of ghost trains if both, for the minimum observation time period, the camera signals (KS) indicate that the region (B) between the rail vehicle (50) and the second marking (72) is unoccupied, and the track section monitoring facility (30) reports that the track section (20) is free at least when the minimum observation time period expires.

7. Method according to one of the preceding claims 4 to 6, wherein the first marking (71) is provided with a first identification symbol (I1) and the second marking (72) is provided with a second identification symbol (I2).

8. Method according to claim 7, wherein before the rail vehicle (50) travels in at the first end (21) of the track section (20) reported as free and before passing the first marking (71), which, on the basis of an evaluation of the first identification symbol (I1), is detected as such, the track section (20) and the region (B) between the first marking (71) and the rail vehicle (50) are reported as free of ghost trains if, for the predefined minimum observation time period, both the camera signals (KS) indicate that the region (B) between the rail vehicle (50) and the first marking (71) is unoccupied, and the track section monitoring facility (30) reports that the track section (20) is free.

9. Method according to one of the preceding claims 7 to 8, wherein after travelling out from the track section (20) and after passing the second marking (72), the track section (20) and the region (B) between the second marking (72), which, on the basis of an evaluation of the second identification symbol (I2), is detected as such, and the rail vehicle (50) are reported as free of ghost trains if both, for the minimum observation time period, the camera signals (KS) indicate that the section between the rail vehicle (50) and the second marking (72) is unoccupied, and the track section monitoring facility (30) reports that the track section (20) is free at least when the minimum observation time period expires.

10. Method according to one of the preceding claims, wherein - 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 at least also monitored using the camera (81, 82) attached to the rail vehicle (50).

11. Method according to one of the preceding claims, wherein - the track section (20) is equipped with a first marking (71) at a first end (21) and with a second marking (72) at its other second end (22), - at least one front camera (81) is attached in a section of the rail vehicle (50) that is at the front, when viewed in the direction of travel (F), and is at least also oriented towards the front from an optical perspective, - at least one rear camera (82) is attached in a section of the rail vehicle (50) that is at the rear, when viewed in the direction of travel (F), and is at least also oriented towards the rear from an optical perspective, - before the rail vehicle (50) travels into the track section (20), the region (B) between the rail vehicle (50) and the first marking (71) is at least also monitored using the at least one front camera (81) and - after travelling out from the track section (20), the region (B) between the rail vehicle (50) and the second marking (70, 71, 72) is at least also monitored using the at least one rear camera (81).

12. Ghost train detection facility (90), comprising - an image processing facility (91), which is embodied to evaluate camera signals (KS) of at least one camera (81, 82) before a rail vehicle (50) travels into a track section (20) reported as free by a track section monitoring facility (30) or after travelling out from the track section (20) with regard to the region (B) between the rail vehicle (50) and an optically detectable marking (70, 71, 72) attached in the track section (20) or at an end of the track section (20), and to report that the region between the marking (70, 71, 72) and the rail vehicle (50) is free if the camera signals (KS) indicate that the region (B) between the rail vehicle (50) and the marking (70, 71, 72) is unoccupied, and otherwise to report it as occupied, and - a signal processing facility (92), which is embodied in such a manner that, for a predefined minimum observation time period, which is at least as large as the signal processing time (Tv) of the track section monitoring facility (30), it observes a status signal (ZS) of the track section monitoring facility (30) which indicates the occupancy state of the track section (20) and performs ghost train detection on the basis of both an occupancy report of the image processing facility (91) and the status signal (ZS) of the track section monitoring facility (30).

13. Ghost train detection facility (90) according to claim 12, wherein the signal processing facility (92) is embodied in such a manner that it reports that the track section (20) and the region (B) between the rail vehicle (50) and the marking (70, 71, 72) are free of ghost trains if the image processing facility (91) indicates that the region (B) between the rail vehicle (50) and the marking (70, 71, 72) is unoccupied and, for the predefined minimum observation time period, the track section monitoring facility (30) reports that the track section (20) is free.

14. Ghost train detection facility (90) according to claim 12 or 13, wherein the signal processing facility (92) is embodied in such a manner that it reports that the track section (20) and the region (B) between the rail vehicle (50) and a marking (70, 71, 72) that has already been passed when viewed in the direction of travel are free of ghost trains if, for the minimum observation time period, the image processing facility (91) indicates that the region (B) between the rail vehicle (50) and the marking (72) is unoccupied and the track section monitoring facility (30) reports that the track section (20) is free at least when the minimum observation time period expires.

15. Rail vehicle (50), which comprises - at least one camera (81) and - a ghost train detection facility (90) according to one of the preceding claims 12 to 14 which is connected to the camera (81) .

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