RAIL SYSTEM FOR A RAIL-MOUNTED VEHICLE

Abstract: A rail system comprises a track for a rail-mounted vehicle (18-20) and units (7-14) which are adapted to send information to the rail-mounted vehicle (18-20). It comprises at least one group of units with at least one pair of units (7-14), which are arranged in a spaced-apart manner in the transverse direction of the track and which are adapted to send information about the position of each unit in the transverse direction of the track and identity information which identifies the group of units. A rail-mounted vehicle (18-20) which is adapted to the rail system comprises a first receiver (48) and a second receiver (49) which are spaced-apart transversely of the direction of travel of the rail-mounted vehicle, for receiving signals from a unit each (7-14) with identity information which identifies the unit (7-14) and position information about the position of the unit (7-14) transversely of the direction of travel of the vehicle.

Description: RAIL SYSTEM FOR A RAIL-MOUNTED VEHICLE Field of the Invention The present invention relates to a rail system and a rail-mounted vehicle according to the preamble to the independent claims. Background Art Rail systems such as railways intended for rail- mounted vehicles are nowadays often provided with automatic control systems, i.e. ATC systems. The function of the ATC systems is to prevent driver's mistakes from causing collisions between rail-mounted vehicles or derailment. The currently existing ATC systems, such as the Swedish ATC, the Danish ATC and the new European standard system ETCS, have the feature in common that along the rail there are arranged what is called markers sending information to a passing train. The markers are arranged along the track at a predetermined, but variable distance from one another. This specific distance is vital for the reliability of the system and is included in the marker telegram as an item of information about the distance to the next marker point in the route of the train. To enable determination of the direction of travel of the train, two markers are arranged one after the other along the track, which markers send different signals so that the order in which a rail-mounted vehicle receives the signal indicates the direction of travel of the train. A drawback of the existing systems is that it is difficult to obtain safety according to one of the so-called SIL classes 1-4 according to EN50129. To obtain high safety, the markers are made so that they will be unlikely to fail. However, this makes them expensive to manufacture. Furthermore, it is in any case very expensive to manufacture the markers with sufficient reliability. If the receiver or marker should fail, no point will be read. The safety in this type of system is therefore always based on the condition that the distance run by the train between two markers is measured and monitored in a fail-safe manner. This is usually carried out by means of a two-channel system. In the ETCS system, for instance the distance run is measured by an odometer as well as by Doppler radar. If a marker is not read at the point where it is expected to be found, owing to a defect in the reader of the train or a defect in the transponder of the marker, the emergency brake of the train is simply applied. A drawback of such a system is that the architecture in this type of system requires the distance between the markers to be sufficiently small to enable measuring of the distance run with sufficient accuracy. A further drawback of this method is that the total cost of the system will be high since markers have to be placed along the entire railway line at given maximum dis- tances. There is thus a need for a system which at a lower a cost than today's systems results in the same great safety or even greater safety and which does not require markers to be placed along the entire distance which is to be run by a rail-mounted vehicle. Summary of the Invention An object of the present invention is to provide a rail system in which units sending position information can be placed at arbitrary distances from each other with retained safety. Another object of the present invention is to provide a rail system in which high safety can be obtained with less expensive units than those used today. A further object is to provide a rail-mounted vehicle which allows high safety with simpler and less expensive units than those used today. These objects are achieved by a rail system and a rail-mounted vehicle according to the independent claims. Preferred embodiments are defined in the dependent claims . A rail system according to the invention comprises a track for a rail-mounted vehicle and units which are adapted to send information to the rail-mounted vehicle. The rail system is characterised in that it comprises at least one group of units consisting of at least one pair of units which are arranged in a spaced-apart manner in the transverse direction of the track and which are adapted to send information about the position of each unit in the transverse direction of the track and identity information identifying the group of units. The track preferably comprises two rails in an ordinary railway track, but alternatively the track comprises one rail only. One rail is used, for example, in rail systems for suspended rail vehicles. Alternatively, the track constitutes part of a magnet rail system, in which case the track includes no rail at all. The units correspond to the markers in a track system according to prior art technique . The units are advantageously arranged in a common main direction. Thus units having a position to the right in the main direction of the track send signals which identify that the unit has a position to the right in the main direction of the track and vice versa. With a rail system according to the invention, increased safety is obtained since it makes it possible for a rail-mounted vehicle to determine its position even if one of the units in a group of units fails. A rail- mounted vehicle can determine in which direction it travels by determining on which side it has the unit that corresponds to the right side in the main direction and on which side it has the unit that corresponds to the left side in the main direction. Thus, the rail-mounted vehicle can establish that it has passed a unit even if one of the units fails. It is unlikely that both units would fail at the same time although the reliability of each of the units is inferior to prior-art technique. As a result, the requirement for reliability of an indi- vidual unit can be set lower than according to prior-art since in most cases information is provided that one of the units in a group of units has failed before the next unit in the group has failed. This enables a safe rail system for rail-mounted vehicles where the risk of derailment and collision is minimised. Since the invention ensures that the units are detected with high safety, it is not necessary, like in prior-art, to arrange units at regular intervals along the track. It is also easy to combine a rail sys- tern according to the invention with a rail system according to prior art . Rail systems advantageously comprise also a control device which is adapted to send in a diversified manner to a rail-mounted vehicle reference identity information identifying a group of units and speed information about the speed which the rail-mounted vehicle is to assume. By sending reference identity information and speed information in a diversified manner, great reliability also regarding the information is obtained. The fact that the control device sends information in a diversified manner means that sending is effected via two separate channels. In the case where the rail system comprises a control device, this is advantageously connected to two radio transmitters and adapted to send the reference identity information and the speed information by each of the radio transmitters at different frequencies. This guarantees greater reliability since a radio transmitter may then fail without the information being fully pre- vented from reaching the train. Each radio transmitter then advantageously sends messages that are associated with each of the units. The messages are advantageously digital messages. At least one of the bits in the messages defines the position of the unit in the transverse direction of the track. Alternatively, the control device is connected to the units and is adapted to send the reference identity information and the speed information via at least two units . Each group of units in the rail system advantageously comprises two pairs of units. This gives the advantage that the probability that all units in a group of units should fail at the same time will be sufficiently small . The term unit is to be interpreted in a wide sense in this context. Advantageously the unit is such as to send information when it obtains power from an external transmitter. The unit is advantageously arranged for electromagnetic radiation. For instance, the unit is a bar code sending modulated light when illuminated. Advantageously the units are transponders which are adapted to be activated and obtain power from an external transceiver. This means that the transponder need not be connected to a power supply, which means that the rail system can be made less expensive. According to a preferred embodiment, the transponder comprises a coil on a ferrite-rod aerial which receives power from the transceiver, and an integrated circuit which ensures that a signal is sent containing information about the position of each unit in the transverse direction of the track and identity information which identifies the group of units. It is advantageous that the units are adapted to send information about the position of each unit in the transverse direction of the track and identity information identifying the group of units. To prevent snow and moisture from affecting the reliability of the transponders, radio frequencies that are not damped by water are advantageously used. Prefer- ably use is made of frequencies in the range 50-500 kHz, advantageously in the range 100-200 kHz. Preferably the unit sends information at the same frequency as the one at which it receives a signal . A rail-mounted vehicle according to the invention is characterised in that it comprises a first receiver and a second receiver, which are spaced-apart transversely of the direction of travel of the rail-mounted vehicle, for receiving signals from a unit each, containing identity information identifying the unit and position information about the position of the unit transversely of the travelling direction of the rail-mounted vehicle. An advantage of such a rail-mounted vehicle is that it makes possible a less expensive and simpler rail sys- tem, which at the same time allows high safety. If one of the receivers should fail, it is still possible to establish the position and direction of the rail-mounted vehicle on the basis of one of the units. Since the probability that both receivers should fail at the same time is very small, units need not be provided at regular intervals along the entire track. Thus, it is only necessary to arrange units at the signal points that are of interest. This makes the solution significantly less expensive than prior art. Advantageously, a rail-mounted vehicle according to the invention also comprises a first calculating means connected to the first receiver, a second calculating means connected to the second receiver, each of the calculating means being adapted to compare the receiv- ed identity information with the identity information received by the second calculating means. This gives the advantage that any errors in the reception of the signal are possibly detected in the comparison between the calculating means, which results in high safety. A rail-mounted vehicle according to the invention advantageously comprises also a first radio receiver adapted to receive signals at a first frequency and connected to the first calculating means, and a second radio receiver adapted to receive signals at a second frequency and connected to the second calculating means, each of the calculating means being adapted to compare reference identity information which identifies a unit and which has been received by one radio receiver, with reference identity information which identifies a unit and which has been received by the other radio receiver, and each of the calculating means being further adapt- ed to compare speed information received by one radio receiver, with speed information received by the other radio receiver. By receiving the information via radio, the rail system will be relatively uncomplicated and by using different radio receivers, the system will also be diversified so that the same information is received via two separate channels. The calculating means are advantageously adapted to send a control signal for adjusting the speed of the rail-mounted vehicle according to the speed information only if the speed information, the reference identity information and the identity information agree in both calculating means . It goes without saying that the above features can be combined in the same embodiment. In order to further illustrate the invention, detailed embodiments will now be described, without the invention being considered restricted to these embodiments . Brief Description of the Drawings Fig. 1 illustrates a rail system and a rail-mounted vehicle according to a preferred embodiment of the present invention. Fig. 2 shows in greater detail a rail system and a rail-mounted vehicle according to the present invention. Fig. 3 is a block diagram which illustrates the function of the rail system in coaction with the rail- mounted vehicle according to the preferred embodiment of the present invention. Fig. 4 shows schematically a unit in the form of a transponder according to a preferred embodiment of the present invention. Description of Preferred Embodiments Fig. 1 shows a rail system according to a preferred embodiment of the present invention, which comprises a track 1 consisting of two parallel rails 2. A station in the form of a siding is arranged in connection with the track 1. The siding connects to the track 1 in the crossings 4 and 5. The main direction of the track is indicated by arrow 6. Pairs of units in the form of pairs of transmitters are arranged in the vicinity of the cross- ings 4 and 5. A first pair of transmitters consists of a first right transmitter 7 and a first left transmitter 8. A second pair of transmitters consists of a second right transmitter 9 and a second left transmitter 10. A third pair of transmitters consists of a third right transmit- ter 11 and a third left transmitter 12. A fourth pair of transmitters consists of a fourth right transmitter 13 and a fourth left transmitter 14. The transmitters in each of the pairs of transmitters consist of a transponder sending a message at 125 kHz when it is activated by a transmitter of a passing rail-mounted vehicle. The message from each of the transponders contains identity information in the form of a first code, a second code, a third code and a fourth code together with information whether the transponder is a right or a left transponder. A control device 15 is arranged in the vicinity of the siding 3. The control device is adapted to send information by means of two aerials 16 and 17 at different frequencies to rail-mounted vehicles. A first rail-mounted vehicle 18 is approaching the fourth pair of transmitters 13, 14. Since a second rail- mounted vehicle 19 is on its way to leave the siding 3, the control device sends a signal to the rail-mounted vehicles with reference identity information in the form of the fourth code which identifies the fourth pair of transmitters, speed information that the rail-mounted vehicle is to begin to slow down at the fourth pair of transmitters 13, 14, and stop at the third pair of transmitters if the vehicle moves towards the main direction of the track. The signal also contains reference identity information in the form of the third code which identifies the third pair of transmitters and information about how far it is to the third pair of transmitters . When the first rail -mounted vehicle 18 arrives at the fourth pair of transmitters 13, 14, it receives identity information from each of the transmitters in the fourth pair of transmitters 13, 14 together with information about the position of the transmitter in the transverse direction of the track. The first rail -mounted vehicle compares the received identity information with the reference identity information received with the radio signal for each of the transmitters. If conformity is achieved, the rail-mounted vehicle begins to slow down to stop. If the rail -mounted vehicle passes the third pair of transmitters, the rail-mounted vehicle brakes as fast as possible. The function of the rail-mounted vehicle when passing a pair of transmitters will be described in more detail below. The second rail-mounted vehicle 19 is permitted to leave the siding 3 and run into the track 2. After the second rail-mounted vehicle 19 has left the siding, the first rail-mounted vehicle 18 will be permitted to pass the third pair of transmitters 11, 12. Fig. 2a shows in more detail a third rail-mounted vehicle 20 with a right transceiver 21 and a left transceiver 22. The third rail-mounted vehicle 20 has a first direction of travel indicated by arrow 23. The track 24 on which the rail-mounted vehicle is running has a left transponder 25 and a right transponder 26 in the main direction 27 of the track. Fig. 2b shows the same rail- mounted vehicle when running in the opposite direction 28. In Fig. 2a, the left transceiver 22 will receive information from the left transponder 25 and vice versa, which means that the rail-mounted vehicle can establish that it travels in the main direction of the track. In Fig. 2b, the left transceiver 22 will receive information from the right transponder 26 and vice versa, which means that the rail-mounted vehicle can establish that it tra- vels towards the main direction 27 of the track. Fig. 3 is a block diagram of a control device 30 in a rail system and a rail-mounted vehicle 31. The control device 30 comprises two separate control means 32, 33 which are connected to a first radio transmitter 34 and a second radio transmitter 35 respectively, which in turn are each connected to an aerial 36, 37, respectively. In the control device there is also arranged a comparing means 39, which is adapted to compare data in both control means. The rail -mounted vehicle 31 comprises a first aerial 40 and a second aerial 41, which are connected to a first radio receiver 42 and a second radio receiver 43. The first and the second radio receiver are connected to a first calculating means 44 and a second calculating means 45 respectively. A vehicle comparing means 46 is adapted to compare data in the first calculating means with data in the second calculating means. Each of the calculating means 44, 45 is connected to a central control means 47 which controls the speed of the rail- mounted vehicle. The first and the second calculating means are connected to a first transceiver 48 and a second transceiver 49 respectively, which receive messages from a transponder each. The message received contains identify information which identifies the transceiver and information about the position of the transponder in the transverse direction of the track. The two transmitters 34, 35 are each sending at their own frequency. The first transmitter is sending at 433 MHz while the second radio transmitter is sending at 434 MHz. Common input data regarding the speed of the rail-mounted vehicle is sent on the common contact 38. Input data is, for instance, data indicating that the rail-mounted vehicle is to stop at a predetermined transmitter. Data in the different control means is compared with the comparing means 39. If the data agrees, each of the control means causes the radio transmitters 34 and 35 to send messages containing reference identity informa- tion which identifies a group of transmitters, speed information and direction information. The message is received by the radio receivers 42, 43 in the rail- mounted vehicle 31 and is sent to the first and the second calculating means 44, 45. The vehicle-comparing means 46 compares the data in the two calculating means. If the data does not agree, each of the calculating means sends control signals to the central control means to stop the rail-mounted vehicle. Messages are also read from the first transceiver 48 and the second transceiver 49. If the identity information received by the first transceiver does not conform with the reference identity information received by the second transceiver, the calculating means sends a signal to the central control means to stop the rail-mounted vehicle. If the reference identity information conforms with the identity information, each of the calculating means sends a control signal to the central control means with information about how the speed is to be changed. The central control means in turn controls the rail-mounted vehicle. A message from a transponder contains 32 digital bits, of which the first 15 bits constitute identity information for the transponder together with information whether it is a left transponder or a right transponder, the next 8 bits define the distance to the next transponder and the last 8 bits define the speed at the next transponder. The message from a left transponder is inverted in each bit compared with the message from a right transponder. This gives advantages in the decoding which then can be made with greater reliability. Fig. 4 is a schematic view of a transponder according to an embodiment of the invention. The transponder comprises a coil 50 on a ferrite core 51. The coil is connected to a microchip 52. When the coil is exposed to electromagnetic radiation from a passing transceiver, it takes up power that is released by the microchip which in turn sends the message as described above. A person skilled in the art realises that the invention is not limited to the above embodiments and that several modifications can be made within the scope of the invention. For instance, the unit may consist of a bar code which sends modulated light when illuminated by a transceiver of a passing rail-mounted vehicle.

Claims: CLAIMS 1. A rail system comprising a track for a rail- mounted vehicle and units (7-14) which are adapted to send information to the rail-mounted vehicle (18-20) , c h a r a c t e r i s e d in that it comprises at least one group of units consisting of at least one pair of units (7-14) which are arranged in a spaced-apart manner in the transverse direction of the track and which are adapted to send information about the position of each unit in the transverse direction of the track and identity information identifying the group of units. 2. The rail system as claimed in claim 1, which also comprises a control device (15) which is adapted to send in a diversified manner to a rail-mounted vehicle (18-20) reference identity information identifying a group of units and speed information about the speed which the rail-mounted vehicle is to assume. 3. The rail system as claimed in claim 2, wherein the control device (15) is connected to the units (7-14) and is adapted to send the reference identity information and the speed information via at least two units (7-14) . 4. The rail system as claimed in claim 2, wherein the control device (15) is connected to two radio transmitters (34, 35) and is adapted to send the reference identity information and the speed information by each of the radio transmitters (34, 35) at different frequencies. 5. The rail system as claimed in any one of the pre- ceding claims, wherein each group of units comprises at least two pairs of units (7-14) . 6. The rail system as claimed in any one of the preceding claims, wherein the units (7-14) are transponders which are adapted to be activated and obtain power from an external transceiver (42, 43). 7. A rail-mounted vehicle, c h a r a c t e r i s e d in that it comprises a first receiver (42) and a second receiver (43) , which are spaced-apart transversely of the direction of travel of the rail-mounted vehicle (18-20) , for receiving signals from a unit each, containing identity information identifying the unit (7-14) and position information about the position of the unit transversely of the direction of travel of the rail-mounted vehicle (7-14) . 8. The rail-mounted vehicle as claimed in claim 7, which also comprises a first calculating means (44) con- nected to the first receiver (42) , a second calculating means (45) connected to the second receiver (43) , each of the calculating means (44, 55) being adapted to compare the received identity information with the second calculating means (44, 45) . 9. The rail-mounted vehicle as claimed in claim 8, which also comprises a first radio receiver adapted to receive signals at a first frequency and connected to the first calculating means, and a second radio receiver adapted to receive signals at a second frequency and con- nected to the second calculating means, each of the calculating means being adapted to compare reference identity information which identifies a unit (7, 14) and which has been received by one radio receiver (42, 43), with reference identity information which identifies a unit and which has been received by the other radio receiver (42, 43), and each of the calculating means (44, 45) being further adapted to compare speed information received by one radio receiver with speed information received by the other radio receiver. 10. The rail-mounted vehicle as claimed in claim 9, the calculating means further being adapted to send a control signal for adjusting the speed of the rail- mounted vehicle according to the speed information only if the speed information, the reference identity infor- mation and the identity information agree in both calculating means.

Inventors: GATENFJORD GOERAN, GATENFJORD, GOERAN
Applicants: GATENFJORD GOERAN, NOVOSIGNAL AB, GATENFJORD, GOERAN
Application year: 2001
Main classification: B61L3
IPC codes: B61L3