DEVICE FOR AUTOMATIC DISPENSING OF AN ANTI-ICING AGENT OR A DE-ICING AGENT ON RAILWAY VEHICLES

Abstract

The invention relates to a device for automatic dispensing of a maintenance agent, such as an anti-icing agent or a de-icing agent, on specific parts of a rolling stock travelling on a railway track. The device comprises a dispensing unit, a detection unit configured to generate a detection signal before said rolling stock reaches the dispensing unit, a sensor unit configured to determine position and velocity of the rolling stock, and a control unit. The control unit is configured to receive said detection signal from said detection unit, determine a dispensing schedule based on said rolling-stock velocity, and transmit a control signal to the dispensing unit to control said dispensing unit based on said dispensing schedule. Furthermore, the present inventive concept also relates to an associated method.

Claims

1. A device for automatic dispensing of a maintenance agent, such as an anti-icing agent or a de-icing agent, on specific parts of a rolling stock, such as a locomotive or a carriage, travelling on a railway track, the device comprising: a dispensing unit adapted to dispense said maintenance agent on said specific parts of the rolling stock, a detection unit configured to generate a detection signal before said rolling stock reaches the dispensing unit, a sensor unit configured to determine a position of a part of the rolling stock and generate a position signal, and for determining a velocity of the rolling stock, and a control unit which is configured to receive said detection signal from said detection unit, receive said position signal from said sensor unit, determine a dispensing schedule based on said rolling-stock velocity, said dispensing schedule comprising a time schedule having data about when to dispense the maintenance agent from the dispensing unit and information about a time duration of how long to dispense the maintenance agent from the dispensing unit, and transmit a control signal to the dispensing unit, wherein the control signal is configured to control said dispensing unit based on said dispensing schedule.

2. A device according to claim 1, wherein the detection unit is configured to generate an identification signal, said identification signal comprising data about an identity of the rolling stock, and wherein the control unit is configured to determine if a rolling stock is approved for dispensing operation based on said identification signal.

3. A device according to claim 2, comprising an information database for storing information of previous dispensing operations related to the identity of the rolling stock, and wherein the control unit is configured to determine whether a rolling stock is approved for dispensing operation based on stored information of previous dispensing operations for said rolling stock.

4. A device according to claim 1, wherein said detection unit comprises an antenna unit comprising at least one antenna, and an electronic tracking unit which is adapted to be arranged on or in said rolling stock, the electronic tracking unit being arranged to communicate with said antenna unit.

5. A device according to claim 4, wherein said electronic tracking unit comprises a radio frequency identification tag, RFID tag.

6. A device according to claim 1, wherein the control unit is configured to start a pump connected to the dispensing unit upon receipt of the detection signal from the detection unit and before transmitting the control signal to the dispensing unit.

7. A device according to claim 6, wherein the control unit is configured to open a recirculation valve for recirculating maintenance agent by means of the pump upon receipt of the detection signal, and wherein the control unit is configured to close the recirculation valve before transmitting the control signal to the dispensing unit.

8. A device according to claim 1, wherein the sensor unit comprises a first position sensor and a second position sensor arranged with a gap between them and being arranged with a predetermined distance from the first position sensor to the second position sensor, and wherein a timing device is provided to calculate a time between a signal from the first position sensor and a signal from the second position sensor.

9. A device according to claim 1, comprising a first detection unit, a second detection unit, a first sensor unit and a second sensor unit, wherein the first detection unit is arranged a distance from the dispensing unit in a first direction along the railway track, the second detection unit is arranged a distance from the dispensing unit in the opposite direction along the railway track, the first sensor unit is arranged between the first detection unit and the dispensing unit, and the second sensor unit is arranged between the second detection unit and the dispensing unit.

10. A device according to claim 1, wherein the dispensing unit comprises at least one dispensing member having at least one dispensing arm and a transversely extending portion, the dispensing arm being connectable to the transversely extending portion.

11. A device according to claim 10, wherein the transversely extending portion extends under the railway track in a direction across the railway track.

12. A device according to claim 11, wherein the transversely extending portion extends along a railway sleeper and is fastened to the railway sleeper by means of a fastening device, and wherein the dispensing arm extends in a direction upwards from the transversely extending portion.

13. A method for automatic dispensing of a maintenance agent, such as an anti-icing agent or a de-icing agent, on specific parts of a rolling stock, such as a locomotive or a carriage, travelling on a railway track, the method comprising: generating a detection signal before said rolling stock reaches a dispensing unit for dispensing the maintenance agent, determining a position and a velocity of the rolling-stock by means of a sensor unit, forwarding the detection signal to a control unit and determining a dispensing schedule based on said rolling-stock velocity, said dispensing schedule comprising a time schedule having data about when to dispense the maintenance agent from the dispensing unit and information about a time duration of how long to dispense the maintenance agent from the dispensing unit, and dispensing said maintenance agent based on said dispensing schedule.

14. A method according to claim 13, comprising the steps of generating an identification signal comprising data about an identity of the rolling stock, and determining if a rolling stock is approved for dispensing operation based on said identification signal.

15. A method according to claim 14, comprising the steps of storing information of previous dispensing operations related to the identity of the rolling stock, and determining whether a rolling stock is approved for dispensing operation based on stored information of previous dispensing operations for said rolling stock.

16. A method according to claim 13, comprising the step of pumping maintenance agent in a recirculation line upon detection of a rolling stock and before dispensing of the maintenance agent.

17. A method according to claim 13, comprising the step of dispensing maintenance agent on the rolling stock travelling on a mainline railway track.

18. A method according to claim 13, comprising the steps of detecting a first rolling stock travelling in a first direction on the railway track by means of a first detector, generating a first detection signal before said first rolling stock reaches the dispensing unit, determining the position and the velocity of the first rolling stock by means of a first sensor unit, determining the dispensing schedule based on the velocity of the first rolling stock, dispensing said maintenance agent based on the dispensing schedule for the first rolling stock, detecting a second rolling stock travelling in a second direction on the railway track opposite to the first direction by means of a second detector, generating a second detection signal before said second rolling stock reaches the dispensing unit, determining the position and the velocity of the second rolling stock by means of a second sensor unit, determining the dispensing schedule based on the velocity of the second rolling stock, and dispensing said maintenance agent based on the dispensing schedule for the second rolling stock.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

[0072] FIG. 1 is a schematic perspective/side view of a railway environment in which an embodiment of the inventive dispensing device is implemented.

[0073] FIG. 2 is a schematic top view of the railway environment in FIG. 1, wherein the dispening unit, the antennas unit(s) and the sensor unit are shown.

[0074] FIG. 3 is a perspective view schematically illustrating a pair of dispensing arms which are comprised in the embodiment in FIG. 1. FIG. 4 is a block diagram schematically illustrating an embodiment of the inventive method which is implemented in the dispensing device according to FIGS. 1-3.

[0075] FIG. 4 is block diagram of an embodiment of a method in accordance with the inventive concept.

[0076] FIG. 5 is a schematic top view of the train in FIGS. 1 and 2, wherein placements of RFID tags on both sides of the train are illustrated.

[0077] FIG. 6 is block diagram of an alternative embodiment of a method in accordance with the inventive concept.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0078] Next, an embodiment of the inventive dispensing device will be described with reference to FIG. 1-3.

[0079] FIG. 1 schematically illustrates a side view of a railway environment 100 in which an embodiment of the inventive dispensing device 200, illustrated in a perspective view, is implemented. The railway environment 100 comprises a railway track 102 and a dispensing area 104. The dispensing area 104 comprises a railway track portion on which a rolling stock in the form of a train 110, or a locomotive 110, is adapted to be moved before being subject to a dispensing operation by the dispensing device 200. Additionally, the dispensing area comprises a railway track portion on which the train is adapted to be moved after being subject to the dispensing operation by the dispensing device 200.

[0080] The train 110 is moving on the railway track 102 in the direction indicated by the arrow and having a speed v. It is understood that any number of additional train units, such as train wagons, may be connected to the train 110. In FIG. 1, the train 110 is approaching the dispensing device 200. The environment in which the train 110 is moving is very cold, say between −5° C. and −30° C., and large quantities of ice and snow is present on the train 110, as indicated by the stars on the train 110. The accumulation of ice and snow is prevented by the dispensing device 200 using an anti-ice maintenance agent. Additionally, the dispensing device 200 may supply a maintenance agent to the train 110 for counteracting the formation of ice and snow after the train 110 has passed by a dispensing area 104 in which the dispensing device 200 is located. Specific parts of the train 110 are intended to be sprayed or dispensed by the dispensing device 200 using the maintenance agent as will be explained in detail below.

[0081] The maintenance agent is given by an anti-icing agent or a de-icing agent, or a combination of the two agents, in liquid form. For example, the maintenance agent may comprise glycerine or glycerol. The maintenance agent may also comprise water. For example, water may be mixed with antifreezing agents. However, other maintenance agents are conceivable. For example, glycol may be used. If glycol is used, a collecting unit (not shown) for collecting and reusing or recycling the glycol is preferably used.

[0082] The dispensing device 200 comprises a detection unit 210, which is indicated by a broken line, a control unit 220, and a dispensing unit 230, which also is indicated by a broken line. There is a wireless two-way communication between the detection unit 210 and the control unit 220. Additionally, there is a wireless two-way communication between the detection unit 210 and the dispensing unit 230.

[0083] In the illustrated embodiment, the detection unit 210 comprises an antenna unit 212, and two passive RFID tags 214, 216. It is clear that two passive RFID tags 214, 216 has been chosen for illustrative purposes only and that any number and any types of RFID tags may be used. The antenna unit 212 comprises four antennas 213 and a power source (not shown). There is a wireless two-way communication between the antenna unit 212 and each of the RFID tags 214, 216. A wireless two-way communication is indicated by a double-sided arrow.

[0084] The control unit 220 comprises an electrical unit 222 comprising electronic components for implementing wireless two-way communication with the antenna unit 212 and for receiving wireless detection signals from the RFID tags 214, 216. The control unit 220 unit further comprises a computer unit 224. The computer unit 224 is connected to the electrical unit 222 by means of a cable 223. The computer unit 224 comprises a processor, a database comprising a memory, a telecommunications module, and other components known to a person skilled in the art. The processor is adapted to perform calculations, comparisons, estimates, etc., e.g. based on the received detection signals from the RFID tags 214, 216. The memory in the database may store historic data related to the dispensing device 200. For example, the historic data may be data about previous dispensing operations. These dispensing operations may have been implemented by means of the dispensing device 200, or by other dispensing devices located in other dispensing areas. The historic data may comprise data relating to a dispensing frequency, a dispensing duration, historic dispensing schedules, dispensing pressures, dispensing speeds, geographic dispensing locations, dispensing areas, dispensing areas on the train, a historic speed of the train, a historic position of the train, a historic acceleration of the train, etc.

[0085] Moreover, a reservoir 226 for supplying the maintenance agent to the dispensing unit 230 is connected to the control unit 220 by means of a connection hose 228. A heating device 227 is provided next to the reservoir 226 for heating the maintenance agent to an acceptable temperature, e.g. by taking into account an outside temperature. In a non-limiting example, the maintenance agent is heated to a temperature between 20° C. and 30° C. In another non-limiting example, the maintenance agent is heated to a temperature between −20° C. and 20° C. The connection hose 228 may comprise a heating cable for counteracting a decrease of temperature of the maintenance agent when the railway environment 100 in which the dispensing device 200 is provided has a low temperature, e.g. below −10° C.

[0086] It is clear that the detection unit 210 and the control unit 220 may be located inside or outside the dispensing area 104. In the present embodiment, the detection unit 210 is located outside the dispensing area 104 and the control unit 220 is located inside the dispensing area 104. The dispensing unit 230 is located inside the dispensing area 104.

[0087] The control unit 220 further comprises a pump (not shown) for feeding the maintenance agent from the reservoir 226 to the dispensing unit 230. The control unit 220 may control the pump.

[0088] The dispensing unit 230 is connected to the control unit 220 by means of a connection arrangement 231. The connection arrangement 231 comprises one or several hoses (not shown) for supplying the maintenance agent to the dispensing unit 230. At the dispensing unit 230, the connection arrangement 231 is split into four connection hoses 239.

[0089] The connection arrangement 231 may comprise a heating cable for counteracting a decrease of temperature of the maintenance agent when the railway environment 100 in which the dispensing device 200 is provided has a low temperature, e.g. below −10° C.

[0090] The connection arrangement 231 also comprises at least one electrical wire for connecting the control unit 220 with the dispensing unit 230. Alternatively, however, the control unit 220 may be connected to the dispensing unit 230 by means of a wireless connection.

[0091] Optionally, the connection arrangement 231 may comprise a return hose for circulating back an amount of maintenance agent which has not been used, or which may be recycled.

[0092] The dispensing unit 230 comprises four pairs of dispensing arms 232, wherein each pair comprises two dispensing arms 232 which are provided on opposite sides of the track. The dispensing unit 230 comprises four dispensing arms 232 on each side of the track, see FIG. 2. Thus, the dispensing unit 230 comprises eight dispensing arms 232. It is obvious that this embodiment is non-limiting and that any number of dispensing arms 232 may be used. For illustrative purposes, only one of these dispensing arms 232 is illustrated in FIG. 3.

[0093] The four connection hoses 239 are connected to a respective one of the four pairs of dispensing arms 232.

[0094] Note that in FIG. 2, only the antenna unit 212, the dispensing unit 230 and the sensor unit 320 of the dispensing device 200 is shown. In particular, neither the full detection unit 210, comprising the RFID tags 214, 216, nor the control unit 220 is shown. Additionally, the train 110 has been left out from FIG. 2.

[0095] The four dispensing arms 232 have different heights. According to an alternative embodiment, however, some or all of the arms 232 may have the same heights.

[0096] In the present embodiment, and in what follows, the first, second, third and fourth dispensing arms 232 are identified from the right to the left in FIG. 1. In other words, the train 110 arrives to the first arm 232 first and to the fourth arm 232 last. According to another embodiment, however, the first, second, third and fourth dispensing arms 232 are identified from the left to the right in FIG. 1.

[0097] The first and second dispensing arms 232 are arranged to dispense the maintenance agent on at least a part of an entrance step related to a door 116 of the train 110. The third dispensing arm 232 is arranged to dispense the maintenance agent on at least a side part of the train 110. The fourth dispensing arm 232 is arranged to dispense the maintenance agent on at least a part of an underside of the train 110. Also, a bogie or other selected sections may be dispensed by one or several of the arms 232.

[0098] With reference two FIG. 3, the two dispensing arms 232 comprised in a pair of dispensing arms 232 are connected to each other by means of a transversely extending portion 233, which is comprised in the dispensing unit 230. At least one of the dispensing arms 232 is connecteble to the transversely extending portion 233, e.g. by means of conventional fastening means, such as flanges and screws or similar. Hence, the transversely extending portion 233 can be introduced under a pair of railway rails 108 and connected to the dispensing arm 232 for easy installation. The transversely extending portion 233 is provided in abutment with a side portion of a sleeper 106 on which the pair of railway rails 108 are provided. For example, the transversely extending portion 233 is connected to the sleeper 106 by means of a fastening device (not illustrated), e.g. including screws or similar.

[0099] Each dispensing arm 232 comprises two dispensing nozzles 234, 235. The upper dispensing nozzle 234 has an elongated vertical opening. The lower dispensing nozzle 235 has an elongated horizontal opening. Thereby, the two dispensing nozzles 234, 235 give rise to different dispensing patterns, or spray patterns. Note that both dispensing arms 232 in FIG. 3 comprise dispensing nozzles 234, 235, but that the upper 234 and lower 235 on the left arm 232 in FIG. 3 cannot be seen. However, also the left arm 232 comprises nozzles 234, 235 which are directed substantially toward a center portion of the railway track 102. For example, each dispensing arm 232 comprises a non-return valve, e.g. at each of the nozzles 234, 235.

[0100] The dispensing nozzles 234, 235 may dispense the maintenance agent at least on a side part or an underside of the train 110, such as part of a bogie, an entrance step, or a side portion, etc.

[0101] The transversely extending portion 233 comprises three dispensing nozzles 236. The dispensing nozzles 236 have elongated openings provided in the transverse direction.

[0102] The three dispensing nozzles 236 may dispense the maintenance agent on at least a part of an underside of the train 110.

[0103] The dispensing nozzles 234, 235, 236 may be rotated and/or inclined. Thereby, a more directed dispensing pattern may be provided. A rotation and inclination operation of the dispensing nozzles 234, 235, 236 may be implemented manually. More preferably, however, the rotation and inclination operation of the dispensing nozzles 234, 235, 236 are implemented automatically by means of a nozzle adjustment unit (not shown) provided in relation to each nozzle and connected to the control unit 230.

[0104] The dispensing unit 230 comprises valves (not shown) which may open or close each of the dispensing nozzles 234, 235, 236 for dispensing the maintenance agent. The valves are configured to be opened or closed by receiving a control signal. The control signal is received from the control device 220. The valves may be gradually opened. Alternatively, the valves are arranged at the control unit 220, wherein a plurality of connection hoses are arranged between the valves and the dispensing units 230.

[0105] The dispensing unit 230 also may comprise a return valve (not shown) which is connected to the return hose in the connection arrangement 231.

[0106] According the present embodiment, the dispensing device 200 further comprises a sensor unit 300 which is electrically connected to the control unit 220 by means of the cable 310, see FIG. 1. Clearly, according to an alternative embodiment, this connection may be implemented wirelessly. The sensor unit 300 is arranged for providing a position and a velocity of the rolling stock. For example, the sensor unit 300 comprises first and second sensors, such as a first magnetic sensor 302 and second magnetic sensor 304 which are provided on the rails 108. The second magnet sensor 304 is provided closer to the dispensing unit 230 than the first magnet sensor 302. Each of the sensors is adapted to generate a signal when a predetermined part of the rolling stock passes the sensor. More specifically, each magnetic sensor 302, 304 is adapted to generate a signal when a wheel flange 112, 114 of a wheel of the train 110 is in magnetic communication with the magnetic sensor 302, 304. The magnetic communication may be established by the wheel flange 112, 114 being very close to, passing by, or abutting, the magnetic sensor 302, 304. Alternatively, each magnetic sensor 302, 304 is adapted to generate a signal when a wheel axle of the train 110 is in magnetic communication with the magnetic sensor 302, 304. The distance between the sensors 302, 304 is predetermined, wherein the velocity of the train is calculated, e.g. by means of calculating means in the sensor unit 300 or in the control unit 220.

[0107] Further, the dispensing device can comprise a comparing unit 330 for comparing a velocity provided by the sensor unit 300 and a velocity provided by means of the detection unit 210. In the present embodiment, the comparing unit 330 is provided in the control unit 220. It is understood, however, that the comparing unit 330 may be provided in other locations, e.g. in the sensor unit 320.

[0108] The dispensing device 200 is connected to a computer device 400. More specifically, the computer unit 224 in the control unit 220 is adapted for wireless two-way communication with the computer device 400. The computer device 400 and the computer unit 224 are connected to a wireless computer network. Alternatively, however, the computer device 400 may be configured to communicate with the telecommunications module (not shown) comprised in the computer unit 224. The telecommunications module may implement mobile communication between the control unit 220 and the computer device 400, using e.g. General packet radio service, GPRS, or a similar technology well-known to a person skilled in the art.

[0109] The computer device 400 may be a stationary computer or a portable computer device, such as a, laptop, a smart phone or an ipad.

[0110] Moreover, the computer device 400 is connected to a server 410. In the present embodiment, the server is located remotely from the dispensing unit 230.

[0111] Thereby, the computer device 400 may retrieve historical data of the train 110 from a database comprised in the server 410. Examples of historical data have been explained in the above. An operator associated with the dispensing operation may control functions and settings related to the operation by means of the computer 400. The computer 400 may be arranged to receive an e-mail or a SMS message from the dispensing device 200 for informing the associated operator about a status of the device 200, e.g. related to the operation or service of the device, or the supply of the maintenance agent.

[0112] Next, an embodiment of the inventive method for automatic dispensing of a maintenance agent will be described with reference to FIGS. 1-5. First, the train 110 is moving in the railway environment 100 on the railway track 102, approaching the dispensing area 104. The train 110 has a velocity v. For example the train 110 is moving on a mainline railway track, optionally at a transport speed for transporting cargo or passengers as scheduled without any dispensing operation.

[0113] When the train 110 enters the dispensing area 104 or, by passing by a certain reference point on the railway track 102 before the dispensing area, the detection unit 210 is activated and generates a signal. For example, the passive RFID tag 214 becomes energized by the antenna unit 212. For example, the reference point is a point at which the RFID tag 214 may be sufficiently energized for generating a signal. Optionally, the reference point may be a predetermined point on the railway track 102, such as 50-100 m from the dispensing unit 230.

[0114] The detection unit 210 generates a detection signal and an identification signal. For example, after being energized, the RFID tag 214 generates the detection signal and the identification signal. The detection signal and the identification signal are sent to the control unit 220. They are received by the electrical unit 222 and communicated to the computer unit 224. The control unit 220 determines by means of the identification signal and stored historical information of the identified train 110 if the train 110 is approved for dispensing operation or not. Further, the detection signal activates the pump for pumping maintenance agent from the reservoir to set the dispensing device in a mode for instant dispensing operation. For example the control unit 220 is adapted to activate the pump and open a recirculation valve of a recirculation line to pump maintenance agent in said recirculation line upon receipt of the detection signal. For example, the maintenance agent is pumped from the reservoir 226 and around in the recirculation line and back to the reservoir 226.

[0115] Then the train 110 passes the sensor unit 300 for determining the speed and position of the train 110. The sensor unit 300 generates position signals and optionally also a velocity signal and sends it to the control unit 220. Alternatively, the control unit 220 determines the velocity of the train 110 based on the position signals from the sensor unit 300. For example, the velocity is determined by a single reference point, such as a wheel or wheel axle of the train. For example, the velocity is determined for each single reference point, such as each wheel or each wheel axle of the train, passing the sensor unit 300. Then the control unit 220 determines the dispensing schedule for the train 110 based on the velocity of the train 110 and the position thereof. For example, the dispensing schedule is based on the velocity and detected positions of the wheels or wheel axles of the train 110. For example, the dispensing schedule is also based on the identity of the train 110 as provided by the detection unit 210, e.g. so as to identify specific positions for dispensing maintenance agent, such as entrance steps. For example, the database includes information about the train 110, such as type of train, dimensions, etc.

[0116] When an estimated time of arrival of the all the dispensing regions 610, 620 in front of the dispensing nozzles 234, 235, 236 has been established, the control unit 220 sends a control signal to the dispensing unit 230, e.g. via the electrical wire in the connection arrangement 231 or through a wireless connection. The control signal controls the operation of the valves as has been described above. The valves may be opened or closed for controlling the dispensing nozzles 234, 235, 236, thereby controlling the dispensing of the maintenance agent. For example, the recirculation valve is closed a short time before opening the valves to the dispensing nozzles, building up a high pressure in the dispensing unit for immediate and fast dispensing operation. From the estimated time of arrival determined by means of the position and velocity of the train 110, the dispensing schedule may be determined. Hence, the dispensing device 200 includes a timing device. For example, the timing device is included in the control unit 220. The dispensing schedule optionally takes into account other parameters, such as the acceleration or deceleration of the train 110, a predetermined duration of the dispensing operation, historical data, etc. The control unit 220 retrieves historic data from the memory in the computer unit 224 or from the server 410 by means of the computer device 400. Data related to statistics, diagnostics and management data may be retrieved from the memory. Thereby, the data may be reviewed and reports based on the data may be generated.

[0117] As has been described above in the summary, the distance between the dispensing nozzle 234, 235, 236 and the dispensing region 610, 620 has to be compensated for, since it takes some time for the maintenance agent to reach the dispensing region 610, 620 on the train 110, since the dispensing speed of the maintenance agent is finite. The finiteness of the speed of the electrical signals, wired or wireless, may also have to be compensated for. Then, the maintenance agent is dispensed on the train 110 based on the dispensing schedule. The dispensing schedule is based on velocity and position of the train 110 and also on time as the distances between different components of the dispensing device 200 are known, and optionally also on the identity of the train 110.

[0118] Next, an alternative embodiment of the inventive method for automatic dispensing of a maintenance agent will be described with reference to FIGS. 1-5. In FIG. 4 an embodiment of the inventive method (Box 500) is schematically illustrated in a block diagram. The method is implemented in the dispensing device 200 according to FIGS. 1-3 and FIG. 5.

[0119] First, the train 110 is moving in the railway environment 100 on the railway track 102, approaching the dispensing area 104. The train 110 has a velocity v.

[0120] When the train 110 enters the dispensing area 104, by passing by a certain reference point on the railway track 102, the passive RFID tag 214 becomes energized by the antenna unit 212. Subsequently, the passive RFID tag 216 becomes energized by the antenna unit 212.

[0121] The reference point is a point at which the RFID tag 214 or 216 may be sufficiently energized for generating a signal. Optionally, the reference point may be a predetermined point on the railway track 102.

[0122] After being energized, the RFID tag 214 generates a detection signal (Box 510). The detection signal is sent to the control unit 220. It is received by the electrical unit 222 and communicated to the computer unit 224.

[0123] After being energized, the RFID tag 216 generates a detection signal (Box 510). The detection signal is sent to the control unit 220. It is received by the electrical unit 222 and communicated to the computer unit 224.

[0124] A time stamp associated to each of the detection signals are established by the computer unit 224. The detection signal sent from the first RFID tag 214 is associated with a first time stamp τ.sub.1 while the detection signal sent from the second RFID tag 216 is associated with a second time stamp τ.sub.2.

[0125] The distance between the two RFID tags 214 and 216 which are provided in the train 110 is given by Δd, see FIG. 5.

[0126] Thereafter, the speed v.sub.det of the train 110 is determined based on the detection signals (Box 520). More specifically, the processor comprised in the computer unit 224 performs this calculation. First, the time difference Δττ.sub.2−τ.sub.1 is formed. Thereafter, the speed is determined by means of the formula v.sub.det=Δd/Δτ. In fact, this is an average speed estimate of the train 110 during the time ΔT.

[0127] It is understood that this is just one way of establishing the speed v.sub.det. Other ways of establishing the speed v.sub.det are possible.

[0128] Next, when the train 110 passes by the sensor unit 300, the speed v of the train 110 may be determined in a second, independent way. As has been described in the above, a speed v.sub.M of the train 110 may be determined. The procedure of determining v.sub.M has been described in the summary section above in to non-limiting examples.

[0129] By means of the comparing unit 330, the speed v.sub.det determined based on the detection signals is compared with the velocity v.sub.M determined by the sensor unit.

[0130] In a first non-limiting example, the difference Δv=v.sub.det−v.sub.M is formed. If Δv is smaller than a predetermined threshold value Δv.sub.T, the estimated speed v.sub.det is considered to be acceptable.

[0131] In a second non-limiting example, the difference Δ=(v.sub.det−v.sub.M)/v.sub.det is formed. If Δ is smaller than a predetermined threshold value Δ.sub.T, the estimated speed v.sub.det is considered to be acceptable.

[0132] For example, the threshold values Δv.sub.T and Δ.sub.T may be retrieved from the memory in the computer unit 224 or from the server 410. The threshold values may be determined by considering the historic data.

[0133] In a third non-limiting example, an estimated speed of the train 110 is formed by the average value V=(v.sub.det+v.sub.M)/2.

[0134] Additionally, the magnetic sensors 302, 304 may be used for determining a position and an acceleration, or deceleration, of the train 110, and act as triggers for specific dispensing areas 104.

[0135] The speed v.sub.det is an estimation of the true speed v.

[0136] All the distances between the RFID tags 214 and 216 and the regions on the train 110 which are to be dispensed with the maintenance agent are assumed to be known, see FIG. 5. For example, the distance between the first RFID tag 214 and a first dispensing region 610 is d.sub.1 and the distance between the second RFID tag 216 and a second dispensing region 620 is d.sub.2. There may be additional dispensing regions (not shown). The distance from a front end of the train 110 to the first dispensing region 610 is d.sub.3. The distance from a back end of the train 110 to the second dispensing region 620 is d.sub.4.

[0137] Based on the speed V.sub.det, and at least one of the distances d.sub.1, d.sub.2, d.sub.3, d.sub.4 and Δd, an estimated time of arrival of all the dispensing regions 610, 620 in front of the dispensing nozzles 234, 235, 236 may be determined.

[0138] When an estimated time of arrival of the all the dispensing regions 610, 620 in front of the dispensing nozzles 234, 235, 236 has been established, the control unit 220 sends a control signal to the dispensing unit 230 via the electrical wire in the connection arrangement 231. The control signal controls the operation of the valves as has been described above. The valves may be opened or closed for controlling the dispensing nozzles 234, 235, 236, thereby controlling the dispensing of the maintenance agent.

[0139] From the estimated time of arrival, a dispensing schedule may be determined (Box 530). The dispensing schedule takes into account other parameters, such as the speed of the train 110, the acceleration or deceleration of the train 110, a predetermined duration of the dispensing operation, historical data, etc. The control unit 220 retrieves historic data from the memory in the computer unit 224 or from the server 410 by means of the computer device 400.

[0140] Data related to statistics, diagnostics and management data may be retrieved from the memory. Thereby, the data may be reviewed and reports based on the data may be generated.

[0141] As has been described above in the summary, the distance between the dispensing nozzle 234, 235, 236 and the dispensing region 610, 620 has to be compensated for, since it takes some time for the maintenance agent to reach the dispensing region 610, 620 on the train 110, since the dispensing speed of the maintenance agent is finite. The finiteness of the speed of the electrical signals, wired or wireless, may also have to be compensated for.

[0142] Finally, the maintenance agent is dispensed on the train 110 based on the dispensing schedule (Box 540). This operation has been detailed above.

[0143] Next, a complementing embodiment of the present inventive concept will be described with reference to FIGS. 2 and 5.

[0144] Since there are four dispensing arms 232 provided on each side of the railway track 102, cf. FIG. 2, the train 110 may be dispensed with the maintenance agent on both sides of the train 110.

[0145] Since there are four dispensing arms 232 provided on each side of the railway track 102, and RFID tags 214, 216, 714, 716 are provided on both sides of the train 110, see FIG. 5, the train 110 may be dispensed when approaching the dispensing unit from either direction, i.e. from the right or from the left in FIGS. 1 and 2. The antenna unit 212 is provided on the left-hand side of the track 102 in the direction of motion of the train 110, as indicated by the arrow. Typically, but not exclusively, the antenna unit 212 may only communicate with RFID tags 214, 216 which are provided on the same side on the train 110 as the antenna unit 212 is located, i.e. on the left-hand side of the train 110 in its direction of motion. Therefore, according to an alternative embodiment, there is provided an additional antenna unit 912 on the other side of the train 110, i.e. on the right-hand side of the track 102 in the direction of motion of the train 110. Thus, the antenna unit 912 is adapted to communicate with RFID tags 714 and 716 which are provided on the right-hand side of the train 110 in its direction of motion. Other details related to the antenna unit 912 and the RFID tags 714, 716 are analogous to those described above in relation to the antenna unit 212 and the tags 214, 216.

[0146] According to one embodiment the dispensing device 200 comprises at least two detection units 210 and at least two sensor units 300, arranged along the railway track on different sides of the dispensing unit 230 so that a train 110 can approach the dispensing device 200 from either direction. For example the dispensing device 200 comprises four sensor units 300, one on each rail of the railway track, wherein two sensor units 300 are arranged on each side of the dispensing unit 230.

[0147] Optionally, the dispensing device 200 may further comprise a camera unit (not shown). The camera unit may monitor the dispensing operation before and/or after the train 110 passes the dispensing unit 230. The camera unit is adapted to record at least one of an image, a video or an infrared image of the train 110 and/or a part of the dispensing area 104. Data recorded by the camera unit may be stored in the memory and later retrieved therefrom as historical data.

[0148] FIG. 6 is block diagram of an alternative embodiment of a method in accordance with the inventive concept.

[0149] First, when no train 110 is nearby the dispensing area 104, the dispensing device 200 is in an idle mode (Box 910). When a train 110 is detected by the detection unit 210, an identification signal is sent to the control unit 220. The identification signal comprises data about an identity of the train 110. Optionally, the identification signal may comprise additional operational data, such as historic data, about the train 110. Alternatively, the operational data may be retrieved from the memory. The control unit 220 processes the information signal together with the operational data and determines whether the train 110 is approved for spraying (Box 920).

[0150] If the train 110 is not approved for spraying, the dispensing device 200 returns to the idle mode.

[0151] If the train 110 is approved for spraying, the control unit 220 sends a confirmation signal to the detection unit 210 which is instructed to send input signals to the control unit 220, which are collected by the control unit 220 (Box 930). The input signal may be a detection signal.

[0152] Then, the speed of the train 110 is determined based on the input signals (Box 940) and, thereafter, a dispensing schedule based on the determined speed is determined (Box 950). These steps have been detailed above in another embodiment.

[0153] The control unit 220 then determines when to spray (Box 960). If it is too early, more input signals may be collected, thereby returning to Box 930. Hence, a continuous update about the velocity may be provided. If it is time to spray, the control unit 220 sends a control signal to the dispensing unit 960 which starts spraying based on the dispensing schedule (Box 970) as has been described above. Clearly, additional input signals may be collected during the spraying operation if needed. After the spraying, the dispensing device returns to the idle mode.

[0154] The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. For example, the inventive dispensing device may be utilized for a rolling stock comprising a plurality of train units. In addition, there may be a collection tray provided in relation to the dispensing unit for collecting the dispensing agent and melted water from the ice and the snow. The collected liquids may be recycled, e.g. by means of purification, or disposed with.