Patent Grant
11104361
The present invention relates in general to railroad signaling systems and in particular to a railroad virtual track block system.
Block signaling is a well-known technique used in railroading to maintain spacing between trains and thereby avoid collisions. Generally, a railroad line is partitioned into track blocks and automatic signals (typically red, yellow, and green lights) are used to control train movement between blocks. For single direction tracks, block signaling allows to trains follow each other with minimal risk of rear end collisions.
However, conventional block signaling systems are subject to at least two significant disadvantages. First, track capacity cannot be increased without additional track infrastructure, such as additional signals and associated control equipment. Second, conventional block signaling systems cannot identify broken rail within an unoccupied block.
The principles of the present invention are embodied in a virtual “high-density” block system that advantageously increases the capacity of the existing track infrastructure used by the railroads. Generally, by dividing the current physical track block structure into multiple (e.g., four) segments or “virtual track blocks”, train block spacing is reduced to accurately reflect train braking capabilities. In particular, train spacing is maintained within a physical track block by identifying train position with respect to virtual track blocks within that physical track block. Among other things, the present principles alleviate the need for wayside signals, since train braking distance is maintained onboard the locomotives instead of through wayside signal aspects. In addition, by partitioning the physical track blocks into multiple virtual track blocks, broken rail can be detected within an occupied physical track block.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
The principles of the present invention and their advantages are best understood by referring to the illustrated embodiment depicted in
Two methods of train detection are disclosed according to the present inventive principles. One method determines rail integrity in an unoccupied block. The second method determines train positioning within an occupied block in addition to rail integrity. The following discussion describes these methods under three different exemplary situations: (1) the system at rest (no trains) within the physical track block; (2) operation with a single train within the physical track block; (3) and operation with multiple trains within the physical track block. In this discussion, Track Code A (TC-A) is the available open sourced Electrocode commonly used by the railroads and is carried by signals transmitted via at least one of the rails of the corresponding physical track block. Track Code B (TC-B) is particular to the present principles and provides for the detection of train position within one or more virtual track blocks within an occupied physical track block and is preferably carried by signals transmitted via at least one of the rails of the corresponding physical track block. TC-A and TC-B may by carried by the same or different electrical signals. Preferably, either TC-A or TC-B is continuously transmitted. Generally, TC-A is dependent on a first location sending a coded message to a second location and vice versa (i.e., one location is exchanging information via the rail). On the other hand, TC-B is implemented as a reflection of the transmitted energy using a transceiver pair with separate and discrete components. With TC-B, the system monitors for reflections of the energy through the axle of the train.
A Virtual track block Position (VBP) message represents the occupancy data, determined from the TC-A and TC-B signals and is transmitted to the computers onboard locomotives in the vicinity, preferably via a wireless communications link. The following discussion illustrates a preferred embodiment and is not indicative of every embodiment of the inventive principles. TC-A is preferably implemented by transmitter-receiver pairs, with the transmitter and receiver of each pair located at different locations. TC-B is preferably implemented with transmitter-receiver pairs, with the transmitter and receiver of each pair located at the same location. The signature of the energy from the transmitter is proportional to the distance from the insulated joint to the nearest axle of the train.
The section of track depicted in
As indicated in the legends provided in
According to the present invention, each physical track block 101a-101d is partitioned into multiple virtual track blocks or “virtual track blocks”. In the illustrated embodiment, these virtual track blocks each represent one-quarter (25%) of each physical track block 101a-101d, although in alternate embodiments, the number of virtual track blocks per physical track block may vary. In
In particular, the train has entered virtual track block H2 of physical track block 101c and house #2 (103b) accordingly generates a 0 for virtual track block H2 in its VBP message. House #3 (103c) now generates and transmits a VBP message of 00000000 for virtual track blocks A3-H3, due to both sides of the insulated joint 102c being shunted within the nearest virtual track blocks. Table 3 breaks down the codes for the scenario of
The right approach of house #2 (103b) is still not receiving TC-A from house #3 (103c) and house #2 therefore continues to transmit TC-B to the right to detect the virtual track block position of the train within physical track block 101c. With the train positioned within virtual track blocks F2-Hz, house #2 (103b) generates and transmits a VBP message of 11111 for virtual track blocks Az-E2 and 000 for virtual track blocks F2-H2.
House #3 (103c) transmits TC-B to the left and TC-A to the right since physical track block 101d is no longer occupied. Specifically, with the train positioned in virtual track blocks B3-D3, house #3 (103c) generates a VBP message of 0000 for virtual track blocks A3-D3 and 1111 for virtual track blocks E3-H3. Table 4 breaks-down the codes for the scenario of
The left approach of house #3 (103c) is still not receiving TC-A from house #2 (103b) and continues to transmit TC-B to the left to determine the virtual track block position of the train within physical track block 101c, which in this case is virtual track blocks A3-B3. House #3 (103c) also transmits TC-B to the right as well, since physical track block 101d to the right is no longer receiving TC-A from the house to its right (not shown). This indicates a second train is on the approach to house #3 (103c) from the right. House #3 (103c) accordingly generates a VBP message of 00 for virtual track blocks A3-B3, 11111 for virtual track block C3-G3, and 0 for virtual track block H3. Table 5 breaks-down the codes for the scenario of
The right approach of house #2 (103b) and the left approach of house #3 (103c) are now transmitting and receiving TC-A signals. House #3 (103c) continues to transmit TC-B to the right and detects the second train within virtual track blocks F3-H3 of physical track block 101d. House #3 (103c) therefore generates a VBP message of 11111 for virtual track blocks A3-E3 and 000 for virtual track blocks F3-H3. Table 6 breaks-down the codes for the scenario of
Specifically, from the TC-B signaling, house #2 detects the first train within virtual track blocks A2-B2, virtual track blocks C2-G2 as unoccupied, and the second train within virtual track block H2. House #2 (103b) therefore generates and transmits a VBP message of 00 for virtual track blocks A2-B2, 11111 for virtual track blocks C2-G2, and 0 for virtual track block H2. The second train is now in physical track block 101c between house #2 (103b) and house #3 (103c), as well as in physical track block 101d between house #3 (103c) and the house to the right of house #3 (103c) (not shown). In this case, house #3 (103c) generates a VBP message of 00000000 for virtual track blocks A3-H3, due to both sides of insulated joint 102c being shunted within the nearest virtual track blocks. Table 7 breaks-down the codes for the scenario of
According to the principles of the present invention, determining whether a virtual track block is occupied or unoccupied can be implemented using any one of a number of techniques. Preferably, existing vital logic controllers and track infrastructure are used, and the system interfaces with existing Electrocode equipment when determining if a virtual track block is unoccupied.
In the illustrated embodiment, the system differentiates between virtual track blocks that are 25% increments of the standard physical track blocks, although in alternate embodiments physical track blocks may be partitioned into shorter or longer virtual track blocks. In addition, in the illustrated embodiment, in the event of a broken rail under a train, the vital logic controller records, sets alarms, and indicates the location of the broken rail to the nearest virtual track block (25% increment of the physical track block).
Preferably, the system detects both the front (leading) and rear (trailing) axles of the train and has the ability to detect and validate track occupancy in approach and advance. The present principles are not constrained by any particular hardware system or method for determining train position, and any one of a number of known methods can be used, along with conventional hardware.
For example, wheel position may be detected using currents transmitted from one end of a physical track block towards the other end of the physical track block and shunted by the wheel of the train. Generally, since the impedance of the track is known, the current transmitted from an insulated joint will be proportional to the position of the shunt along the block, with current provide from in front of the train detecting the front wheels and current provided from the rear of the train detecting the rear wheel. Once the train position is known, the occupancy of the individual virtual track blocks is also known. While either DC or AC current can be used to detect whether a virtual track block is occupied or unoccupied, if an AC overlay is utilized, the AC current is preferably less than 60 Hz and remains off until track circuit is occupied.
In addition, train position can be detected using conventional railroad highway grade crossing warning system hardware, such as motion sensors. Moreover, non-track related techniques may also be used for determining train position, such as global positioning system (GPS) tracking, radio frequency detection, and so on.
In the illustrated embodiment, the maximum shunting sensitivity is 0.06 Ohm, the communication format is based on interoperable train control (ITC) messaging, and monitoring of track circuit health is based upon smooth transition from 0-100% and 100-0%.
In the preferred embodiment, power consumption requirements comply with existing wayside interface unit (WIU) specifications. Logging requirements include percentage occupancy, method of determining occupancy, and direction at specific time; message transmission contents and timing; calibration time and results; broken rail determinations; error codes; and so on.
The embodiment described above is based on a track circuit maximum length of 12,000 feet, which is fixed (i.e., not moving), although the track circuit maximum length may vary in alternate embodiments. Although the bit description describe above is a 1 for an unoccupied virtual track block and 0 for an occupied virtual track block, the inverse logic may be used in alternate embodiments.
One technique for measuring track position and generating TC-B is based on currents transmitted from one end of a physical track block towards the other end of the physical track block and shunted by the wheels of the train. Generally, since the impedance of the track is known, the current transmitted from an insulated joint will be proportional to the position of the shunt along the block. Once the train position is known, the occupancy of the individual virtual track blocks is also known.
Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
It is therefore contemplated that the claims will cover any such modifications or embodiments that fall within the true scope of the invention.
The present application is a Divisional Application of U.S. patent application Ser. No. 15/965,680, filed Apr. 27, 2018, which claims the benefit of U.S. Provisional Application Ser. No. 62/502,224, filed May 5, 2017, both of which are incorporated herein in their entireties for all purposes.
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 15965680 | Apr 2018 | US |
| Child | 17247303 | US |
