Patent Application
20220055668
This application claims the benefit of Indian Patent Application Number 202011036380, filed on Aug. 24, 2020, which is hereby incorporated by reference in its entirety.
The present embodiments relate to managing operation of trains, and more particularly, relate to a system and method for preventing collision between trains.
Rail transportation is one of the most popular modes of transportation for movement of goods and passengers. Rail vehicles operating on a common route are managed typically through signaling systems. Such signaling systems are intended to prevent head-on collisions and to maintain a safe headway between rail vehicles running in the same direction. Block signaling systems such as moving block systems and fixed block systems are used for preventing collision between trains operating on a common route, by maintaining a safe distance between the trains. For example, in moving block system, the train position and a corresponding braking curve is continuously calculated by the trains and communicated to wayside equipment. Based on the train position and the braking curve, the wayside equipment further establishes a Movement Authority for the trains. The Movement Authority indicates a permission for a train to move to a specific location within the constraints of the infrastructure with supervision of speed. Such block signaling systems may also employ track circuits, communicatively coupled to the wayside equipment, to determine the train positions. However, communication failures associated with the wayside equipment or the track circuit lead to signaling errors in the block signaling system. On manually driven trains, the driver of the train manages the operation of the train based on visual information pertaining to the Movement Authority received from the wayside equipment. However, it is possible that the driver may fail to pay attention to the visual information, thus leading to violation of the Movement Authority. Such human errors or signaling errors may lead to catastrophic events such as a head-on collision, a near-head on collision, or a rear-end collision between trains.
The scope of the present invention is defined solely by the appended claims and is not affected to any degree by the statements within this summary.
In light of the above, there exists a need for a fail-safe mechanism for preventing collisions between trains.
A system and method for preventing collision between a first train and a second train is disclosed. In one aspect, the system includes at least one first subsystem installed on the first train, where the at least one first subsystem is configured to generate broadcast messages indicative of a status of the first train, and at least one second subsystem installed on the second train. The at least one second subsystem is configured via executable instructions to selectively receive the broadcast message from the at least one first subsystem on the first train. The at least one second subsystem is further configured to determine the status of the first train by analyzing the broadcast message. The at least one second subsystem is further configured to determine an action to be performed at the second train based on the status of the first train, where the action is associated with preventing a collision between the first train and the second train. Further, the at least one second subsystem is configured to generate one or more instructions for performing the action at the second train.
In another aspect, the method includes selectively receiving a broadcast message from at least one first subsystem on a first train, by at least one second subsystem installed on a second train. The method further includes determining a status of the first train, by the at least one second subsystem, based on analysis of the broadcast message. The method further includes determining an action to be performed at the second train, by the at least one second subsystem, based on the status of the first train, where the action is associated with preventing a collision between the first train and the second train. The method further includes generating one or more instructions, by the at least one second subsystem, for performing the action at the second train.
Various embodiments are described with reference to the drawings, where like reference numerals are used in reference to the drawings. Like reference numerals are used to refer to like elements throughout. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments. These specific details need not be employed to practice embodiments. In other instances, well known materials or methods have not been described in detail in order to avoid unnecessarily obscuring embodiments. While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. There is no intent to limit the disclosure to the particular forms disclosed. Instead, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.
In one embodiment, the one or more sensing units 125 are configured to sense at least one parameter associated with an integrity of the train. For example, the one or more sensing units 125 may include tilt sensors installed on one or more rail cars of the train to detect derailment of the rail cars. The one or more sensing units 125 may also include other sensors such as proximity sensors, installed between the rail cars, to detect accidental decoupling of the rail cars.
In another embodiment, the one or more sensing units 125 are configured to detect a real-time location of the train. For example, the one or more sensing units 125 may include a Global Positioning System (GPS) to detect the real-time location. In yet another aspect, the one or more sensing units 125 are configured to measure a real-time speed of the train. For example, the real-time speed is measured using a wheel speed sensor positioned on a wheel of the train. The wheel speed sensor is a specially adapted tachometer that measures a wheel speed of the train. In yet another embodiment, the real-time speed is measured using an accelerometer mounted on the train.
In yet another embodiment, the one or more sensing units 125 are configured to detect a braking status associated with the train. For example, the one or more sensing units 125 include a brake pipe sensing hose attached to a glad-hand coupler on a brake pipe of the train. The brake pipe sensing hose is configured to detect the braking status based on an air pressure within the brake pipe.
In yet another embodiment, the one or more sensing units 125 include at least one transmitting antenna and at least one receiving antenna located at extremities of the train. For example, the transmitting antenna may be located near an end of the train, and the receiving antenna may be located near a head of the train. The transmitting antenna may continuously emit radio-frequency signals of a predefined strength, and the receiving antenna measures a received signal strength (RSS) associated with the radio-frequency signals. Based on the RSS, a length of the train is computed in real-time. In one embodiment, the measurement of the length of the train based on the RSS helps in determining an integrity of the train. For example, the RSS reduces in case of a derailment or accidental decoupling of rail cars on the train, thereby indicating that the integrity of the train is compromised. In an alternate embodiment, the length of the train may also be determined based on GPS sensors located at the extremities of the train. In yet another embodiment, the length of the train may also be determined with the help of track circuits such as axle counters.
Further, sensor data or outputs from each of the one or more sensing units 125 are provided to the message generation unit 105, via a data acquisition unit (not shown). In an embodiment, the message generation unit 105 includes a first processing unit 130 and a first memory 135. The term ‘first processing unit’ 130, as used herein, may be any type of computational circuit, such as, but not limited to, a microprocessor, microcontroller, complex instruction set computing microprocessor, reduced instruction set computing microprocessor, very long instruction word microprocessor, explicitly parallel instruction computing microprocessor, graphics processor, digital signal processor, or any other type of processing circuit. The first processing unit 130 may also include embedded controllers, such as generic or programmable logic devices or arrays, application specific integrated circuits, single-chip computers, and the like. The first memory 135 may be non-transitory volatile memory and non-volatile memory. The first memory 135 may be coupled for communication with the first processing unit 130, such as being a computer-readable storage medium. The first processing unit 130 may execute instructions and/or code stored in the first memory 135 to generate broadcast messages based on the sensor data. More specifically, the message generation unit 105 is configured to process the sensor data to identify a current status corresponding to at least one parameter associated with the train. For example, the parameter may correspond to train integrity, braking status, and/or a geographical location. Based on the current status of the parameter, the broadcast message is generated. A variety of computer-readable instructions may be stored in and accessed from the first memory 135. The first memory 135 may include any suitable element for storing data and machine-readable instructions, such as read only memory, random access memory, erasable programmable read only memory, electrically erasable programmable read only memory, a hard drive, a removable media drive for handling compact disks, diskettes, magnetic tape cartridges, memory cards, and the like.
In the present embodiment, broadcast messages corresponding to a train integrity status, a braking status, and a location status are generated. It is possible to generate other types of broadcast messages that may be used to indicate various operational statuses of the train to another train.
Each of the broadcast messages are generated in the form of data packets. Each of the data packets includes a header section, a payload section, and a trailer section. In an embodiment, the header section may include a sequence number, a device identification number, and a broadcast type identifier. The sequence number is used for reordering of the data packets to retrieve the broadcast message at a second subsystem that receives the data packets. The device identification number is used to uniquely identify the first subsystem or the train. The broadcast type identifier may indicate a type of the broadcast message. The broadcast type identifier may be indicated by alphabets, numbers, or an alphanumeric series. For example, the broadcast type identifier ‘00’ may correspond to train integrity status, the broadcast type identifier ‘01’ may correspond to location status, and the broadcast type identifier ‘10’ may correspond to braking status. The trailer section includes fields such as checksum or a secure key string, that are used for validating integrity of the broadcast message. The payload section is configured based on the type of the broadcast message.
In an example, if the broadcast message corresponds to train integrity status, the payload section includes a length of the train, a geographical location of the train, and a failure time of the train. The length of the train may be determined in real-time based on RSS measured at a receiving antenna as explained earlier. The geographical location of the train is a real-time geographical position of the train obtained from the GPS sensors. The failure time of the train is a timestamp corresponding to time at which the failure of the train is detected (e.g., by the one or more sensing units 125). For example, the time stamp may correspond to Dec. 5, 2019, 10:10 am. The failure may be one of derailment, accidental decoupling of rail cars, or loss of communication with the cab of the driver. The broadcast type identifier in the header section is set to ‘00’.
If the broadcast message corresponds to location status, the payload section includes the length of the train, the geographical location of the train, and a speed of the train. The speed of the train is obtained from the one or more sensing units 125 on the train. The broadcast type identifier in the header section is set to ‘01’.
If the broadcast message corresponds to braking status, the payload section includes the length of the train, the geographical location of the train, and a braking time. The braking time indicates a time duration associated with effecting an emergency brake. In general, the braking time is computed based on a braking curve associated with the train. The payload section further includes a timestamp associated with application of emergency brakes on the train. For example, if a driver of the train applies the emergency brake at time 3:15 pm and the train attains zero speed at 3:16 pm, the braking time is 1 minute, whereas the timestamp corresponds to 3:15 pm. The broadcast type identifier in the header section is set to ‘10’.
The broadcast message is further converted to an analog signal using the DAC 110. The modulation circuit 115 further modulates a carrier signal based on the analog signal using a modulation technique. The frequency of the carrier signal may be a radio frequency specific to communications in a railway network of a region. For example, in the United States, the radio frequency of 457 MHz may be used. However, any suitable frequency may be selected for the purpose of sending such broadcast messages. Non-limiting examples of modulation techniques include amplitude modulation, frequency modulation, phase modulation, phase shift keying, and pulse code modulation. Similar to the radio frequency, any modulation technique may be used based on the specifications or requirements of railway networks in a region. For example, certain regions may specify the use of Frequency Shift Keying (FSK). The modulated carrier signal is further amplified by the power amplifier (not shown) and broadcasted through the first transceiver unit 120. The first transceiver unit 120 may transmit the modulated carrier signal based on a suitable broadcasting technology. In an example, the broadcasting technology may be based on Wi-Fi communication.
The second transceiver unit 205 is configured to receive a broadcast message in the form of a modulated carrier signal from a first subsystem. Further, the demodulation circuit 210 demodulates the modulated carrier signal to generate an analog signal. The analog signal is further processed by the ADC 215. The ADC 215 may employ any known RF sampling technique to generate the broadcast message in digital format from the analog signal. Further, the broadcast message in digital format is provided as input to the train management unit 217. The train management unit 217 further includes a second processing unit 220 and a second memory 225.
The second processing unit 220 executes machine-readable instructions stored in the second memory 225 for preventing collision between a first train where the first subsystem is installed and a second train where the second subsystem is installed, in accordance with a method 300 described below. More specifically, the second processing unit 220 generates one or more instructions for implementing an action for preventing collision between the first train and the second train. The one or more instructions are transmitted to other equipment on the second train through the second transceiver unit 205. In an example, the equipment may include a braking system associated with the second train, and the one or more instructions may be associated with application of brakes for slowing down or stopping the second train. In another example, the equipment may include a display device, and the one or more instructions may be associated with displaying an information to a driver of the train. The equipment further executes the one or more instructions to prevent the collision between the first train and the second train. The equipment may also refer to another second subsystem located on the second train.
The term ‘second processing unit’ 220, as used herein, may be any type of computational circuit, such as, but not limited to, a microprocessor, microcontroller, complex instruction set computing microprocessor, reduced instruction set computing microprocessor, very long instruction word microprocessor, explicitly parallel instruction computing microprocessor, graphics processor, digital signal processor, or any other type of processing circuit. The second processing unit 220 may also include embedded controllers, such as generic or programmable logic devices or arrays, application specific integrated circuits, single-chip computers, and the like.
The second memory 225 may be non-transitory volatile memory and non-volatile memory. The second memory 225 may be coupled for communication with the second processing unit 220, such as being a computer-readable storage medium. The second processing unit 220 may execute instructions and/or code stored in the second memory 225. A variety of computer-readable instructions may be stored in and accessed from the memory 225. The second memory 225 may include any suitable elements for storing data and machine-readable instructions, such as read only memory, random access memory, erasable programmable read only memory, electrically erasable programmable read only memory, a hard drive, a removable media drive for handling compact disks, diskettes, magnetic tape cartridges, memory cards, and the like.
At act 305, a broadcast message from at least one first subsystem (similar to the first subsystem 100) on a first train is selectively received by at least one second subsystem installed on a second train. At first, the second subsystem identifies whether the first subsystem is installed on the same train as the second subsystem, based on the device identification number present in the broadcast message. If yes, the broadcast message is discarded. Otherwise, the second subsystem determines whether the geographical location in the broadcast message corresponds to a parallel track or the same track as the second train. If the first train and the second train are on parallel tracks, the second subsystem may discard the broadcast message. Otherwise, the second subsystem receives the broadcast message based on the corresponding broadcast type identifier. For example, the second subsystem is configured to receive only broadcast messages with broadcast type identifier ‘00’. In another example, the second subsystem is configured to receive only broadcast messages with the broadcast type identifier ‘01’ or ‘10’. In one embodiment, the train management unit 217 instructs the second transceiver unit 205 to retransmit the received broadcast message to another subsystem based on the broadcast type identifier. For example, if the second subsystem is configured to receive broadcast messages with broadcast type identifier ‘01’ or ‘10’, broadcast messages with broadcast type identifier ‘00’ may be retransmitted to another second subsystem on the second train for processing.
At act 310, a status of the first train is determined, by the at least one second subsystem, based on analysis of the broadcast message. For example, if the broadcast message is associated with train integrity, the second subsystem derives a length of the first train, a geographical location of the first train and a failure time associated with the first train from the broadcast message.
At act 315, an action to be performed at the second train is determined, by the at least one second subsystem, based on the status of the first train. The action is associated with preventing a collision between the first train and the second train. For example, the one or more instructions may be associated with application of emergency brakes, controlling a speed of the second train, initiating communication with a central server, or warning a driver of the second train.
In one example, if the broadcast message corresponds to train integrity, a failure time of the first train is determined from the broadcast message. Further, a headway or distance between the first train and the second train is calculated in real-time based on the geographical location of the first train and the failure time. Based on the headway and a speed of the second train, an estimated time of arrival (ETA) at the geographical location of the first train is computed. Based on the ETA, a new speed for the second train is computed using a predefined mathematical relation. The ETA is continuously computed based on broadcast messages that are continuously received from the first train. Consequently, when the ETA approaches a threshold time-limit (e.g., 2 minutes), the second subsystem may compute the new speed for the second train as zero. The new speed of zero indicates application of emergency brakes at the second train.
Similarly, if the broadcast message corresponds to braking status, a braking time of the first train is determined from the broadcast message along with a timestamp associated with the braking. Further, an ETA at the geographical location of the first train is computed based on the braking time and the timestamp associated with the braking. Based on the ETA computed, the second subsystem determines the action to be performed similar to the case of integrity status.
In another example, if the broadcast message corresponds to a location status of the first train, the second subsystem determines the headway between the first train and the second train in real-time based on the geographical location of the first train. Further, a probability of collision between the first train and the second train is estimated. For example, predefined mathematical relationships are used to estimate the probability of collision from the headway. Based on a value of the probability of collision, the second subsystem determines the action to be performed. For example, if the probability of collision is greater than a predefined value of, for example, 0.7, the action is determined as application of emergency brakes. Otherwise, the second subsystem may determine a new speed of the second train based on predefined rules. In an implementation, the speed may be calibrated based on the probability of collision and stored in the form of a calibration curve in a memory of the second subsystem. Further, the action is determined as reducing the speed of the second train to the new speed.
At act 320, one or more instructions, for performing the action at the second train are generated by the at least one second subsystem. The one or more instructions are associated with for example, actuating signals for application of the emergency brakes. In another example, the one or more instructions are associated with actuating signals for application of brakes on the second train such that the speed is controlled. In yet another example, the one or more instructions are associated with sending a message indicating the status of the first train to the central server.
In the present embodiment, the EOTT system on the first train 405 includes a first Head-of-Train unit (HOT) 415 installed in a cab of the first train 405 and a first End-of-Train unit (EOT) 420 installed at a rear end of the first train 405, communicatively coupled to each other over a telemetry link. Further, the first EOT 420 may provide a train integrity status associated with the first train 405 to the first HOT 415 over the telemetry link. The first HOT 415 includes a Cab Display Unit (CDU) (not shown). The CDU may indicate the train integrity status associated with the first train 405 on a display based on data received from the first EOT 420. The first EOT 420 includes a High Visibility Marker (HVM) (not shown) and a Sensing and Braking Unit (SBU) (not shown). The HVM marker may include high intensity LED arrays that provides a visible indication of the presence of the first train 405 to the second train 410. The SBU includes a brake pipe sensing hose and an air braking system.
The first EOT 420 further includes a first subsystem configured to transmit broadcast messages corresponding to train integrity status, braking status, and location status, as explained earlier with reference to
The EOTT system on the second train 410 includes a second HOT 425 installed in a cab of the second train 410 and a second EOT 430 installed at a rear end of the second train, communicatively coupled to each other over a telemetry link.
In the present embodiment, both the second EOT 430 and the second HOT 425 may include separate second subsystems each configured to process different types of broadcast messages. For example, the second subsystem on the second HOT 425 may be configured to process broadcast messages associated with train integrity status and braking status, while the second subsystem on the second EOT 430 may be configured to process broadcast messages associated with location status. Hereinafter, the terms second HOT 425 and the second EOT 430 are used to refer to the respective second subsystems. In the present embodiment, when a train integrity status or a braking status associated with the first train 405 is received, the second HOT 425 compute an ETA at a geographical location of the first train 405. Further, if the ETA is less than a threshold time-limit, the second HOT 425 generates instructions for the second EOT 430 to communicate the status of the first train 405 to a central server. Simultaneously, the second HOT 425 also generates instructions for actuating an emergency braking system of the second train 410. In an embodiment, the second HOT 425 may also generate instructions for displaying a warning message for the driver of the second train 410 on a CDU. The warning message may instruct the driver to manually reduce the speed of the second train 410.
The second EOT 430 may compute the probability of collision between the first train 405 and the second train 410. Based on the probability of collision computed, the second EOT 430 may compute a new speed for the second train 410. Further, the second EOT 430 generates instructions for controlling the speed of the second train 410. The generated instructions are further transmitted to the second HOT 425 in order to control the brake line pressure, in a coordinated manner. Further, the second HOT 425 is configured to identify broadcast messages intended for the second EOT 430, based on the broadcast type identifier and to retransmit the broadcast message to the second EOT 430. In one embodiment, if a transmission radius associated with the first EOT 420 does not reach the second EOT 430, the second HOT 425 receives and retransmits the broadcast message intended for the second EOT 430.
In another embodiment, the system 400 includes a single second subsystem included in the second HOT 425 for processing broadcast messages, as explained earlier using
In another instance, the first train 405 and the second train 410 may run on the same track while heading towards each other. In this case, head-on collisions are prevented in a manner similar to prevention of rear-end collision as described above.
The present embodiments provide a fail-safe mechanism for prevention of collision between trains. More specifically, the present embodiments improve redundancy in existing signaling systems by facilitating communication of statuses between trains through broadcast messages, in addition to communication through wayside signaling units.
While embodiments of the present invention have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions may be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.
The elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent. Such new combinations are to be understood as forming a part of the present specification.
While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011036380 | Aug 2020 | IN | national |
