Patent Grant
7890223
The present invention relates in general to railroad signaling, and in particular, to aspect compliance monitoring systems and methods.
Almost every railway system worldwide use trackside signals to ensure safety and maintain an orderly flow of traffic. In North America, signaling is typically implemented using green, red, and yellow electric lights a traditional signal can include a single light or multiple lights, which, depending on the given state of illumination, present a given aspect conveying a particular indication. (These signals can use individual incandescent bulbs and lenses in a single housing for each color, or use searchlight units, which change color using mechanical or electrical mechanisms in response to electrical control signals.)
There are a number of permissive and absolute indications that can be represented by the signal aspect. For example, in a signal employing two vertically aligned signal lights, an aspect with an illuminated green light above an illuminated green light is typically a “clear” indicating that the train crew can proceed along the upcoming block of track. In contrast, an aspect having an illuminated red light over another illuminated red typically indicates an “absolute stop” to the train crew. For a single light signal, an illuminated green light on a signal stanchion, with or without a numbered plate, is typically also a “clear” indicating that the train crew can proceed. On the other hand, a single illuminated red on a stanchion with a numbered plate typically indicates “stop and precede” at restricted speed, while a single illuminated red on a stanchion without a numbered plate typically indicates “absolute stop”.
Given the significant need to maintain safety by ensuring compliance with signal aspects, efficient and accurate techniques are necessary for monitoring train crew signal compliance, and particularly “red aspect” compliance.
The principles of the present invention are embodied in systems and methods that allow remote compliance monitoring of railroad signal aspects. According to one representative embodiment, a system is disclosed for remotely monitoring compliance with a railroad signal associated with a section of railroad track and includes a remote aspect compliance subsystem for monitoring compliance with an indication for the section of railroad track represented by an aspect of the railroad signal. The remote aspect compliance subsystem selectively generates corresponding compliance messages, which are communicated via a network to server for display and processing.
Embodiments of the present principles advantageously allow a railroad company to remotely monitor train crew signal compliance, and particularly “red aspect” compliance, and thereby improve safety. These improvements are accurate and very efficient to implement and operate.
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
In the illustrated embodiment, server 101 also communicates with a wireless communications network 105, such as a GSM network available through a commercial wireless service provider, such as Cingular. At least one, and normally more, aspect compliance monitors 106 also communicate with wireless communications network 105. As will be discussed in detail below, aspect compliance monitor 106 includes a wireless gateway 107 and a data processor 108.
System 100 also includes a west wheel detector 202a and an east wheel detector 202b. West wheel detector 202a is spaced from a centerline running through west signal 201a by a distance dw and east wheel detector 202b is spaced from a center line running through east signal 202b by distance de. In the embodiment shown in
Generally, aspect compliance monitor 106 is coupled by cables to west and east signals 201a and 201b. For a locomotive traveling in a given direction, an alarm is sounded and a report is generated when a train crew fails to observe a red aspect condition on the corresponding signal 201a or 201b and/or passes through a red aspect at a speed above a predetermined limit.
Current transducers 301a-301b respectively connect through cables 302a-302b to corresponding west red and east red input ports 303a and 303b on aspect compliance monitor 106.
The signals generated by current transducers 301a and 301b couple through ports 303a-303b to computer system 108. Computer system 108 also receives inputs from west wheel detector 202a and east wheel detector 202b through cables 304a and 304b in corresponding input ports west prox 305a and east prox 305b. In the illustrated embodiment, computer system 108a is a BL2600 Wolf Ethernet-enabled single board computer available from Z-World. West and east wheel detectors 202a-202b are preferably WDS2 wheel detectors which clamp on to a rail of selected track section 200, as generally shown in
Aspect compliance monitor 106 communicates with a central dispatch office through a wireless gateway/router 109 and antenna 307. In the illustrated embodiment, wireless gateway/router 109 is a Digiconnect WAM GSM wide area network (WAN) gateway/router.
Aspect compliance monitor 106 also includes an internal power supply, which is a DC to DC converter 308. In the illustrated embodiment, DC to DC converter is a 12V to 24V converter available from Astrodyne, Taunton, Mass.
At block 401, operating parameters, such as the time, the total distance (D1) between west and east wheel detectors 202a and 202b, and the selected alarm speed are input into computer system 108. The alarm speed represents the maximum speed a train crew may run by a signal 201a or 201b with a red aspect. West and east signals 201a and 201b are then monitored at block 402 for a change of aspect.
When, at decision block 403, a change in signal aspect occurs for one or both of west and east signals 201a-201b, the event is time-stamped and the new states for both of east and west signals are recorded. After the time stamp and aspect states are recorded at block 404, or when no change of signal aspect has occurred at decision block 403, procedure 400 continues to block 405 and wheel detectors west and east 202a and 202b are monitored for electrical pulses.
If no input is detected from either wheel detector 202a or 202b at decision block 406, procedure 400 continues to loop back to decision block 403. Otherwise, as each pulse is detected for given west or east wheel detector 202a or 202b, the time is recorded. Assuming that at least one train axle crosses both detectors 202a and 202b, the first detector generating a pulse is the origin detector, and the second detector generating a pulse is the destination detector. The direction of movement is determined by the origin detector 202a or 202b. For example, the first axle on a westbound train will first trigger west wheel detector 202a.
Pulse times continue to be recorded at block 407 as long as pulses continue to be generated for a given period of time (e.g. 30 seconds) at decision block 408. Otherwise, when no pulses have been detected for the selected period of time it is assumed that the train has either stopped or passed by wheel detectors 202a and 202b.
Thereafter, at decision block 409, a determination is made as to whether the pulses for at least four axles have been detected by both east and west detectors 202a and 202b. If this condition is not met, then procedure 400 jumps to block 415, and the accumulated data are discarded. On the other hand, if at least four axles have crossed both detectors 202a and 202b, then a determination is made as to whether the signal for the direction of travel is clear (block 410). If the aspect for signal 201a-201b corresponding to the direction of travel indicates clear, then procedure 400 again jumps to block 415 and the data are discarded. On the other hand, if the corresponding signal has a red aspect, then at block 411, the average speed is calculated. From the calculated average speed, a determination is made at decision block 414 as to whether the calculated average speed exceeds the selected alarm speed. If it has not, then the data are again discarded at block 415. Otherwise, at block 416, a non-compliance event has been detected and alarm message is generated.
The alarm message includes such information as a time stamp; the estimated speed of the train, whether the movement was either an east move or a west move, and the total axle count. The alarm message is then sent to the central office, preferably via network 105 of
The calculation of the average speed at block 411 can be performed using a number of different methods. In the preferred method, two software arrays are generated, one for the original detector and one for the destination detector. The entries in each array are indexed in accordance with the order in which pulses are received from the corresponding detector and store the time accumulated since the first pulse generated by the origin detector. Hence, the first entry in the origin array represents the time that the first pulse was generated when the first axle crosses the origin detector, and is always populated with a zero. The first entry in the destination array, which is paired with the first entry in the origin array, is populated the time the first axle crosses the destination detector. Similarly, the second entry in the origin array is populated with the time the second axle crosses the origin detector and the second entry in the destination array represents the time the second axle crosses the destination detector, and so on.
In the illustrated embodiment, the average speed is calculated when at least four pairs of entries have been generated (i.e. at least four axles have crossed both the origin and destination detectors, as discussed above). For each pair of entries, the difference between the populated times is taken. The average speed is then calculated by dividing the sum of all the calculated time differences by the total number of axles (i.e. the number of pairs of entries).
While the principles of the present invention have been described using red aspect compliance monitoring as an example, these principles are equally applicable to monitoring compliance with all signal aspects, including green and yellow.
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 claims priority to Provisional Application Ser. No. 60/801,441, filed May 18, 2006.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4085913 | Chang | Apr 1978 | A |
| 6179252 | Roop et al. | Jan 2001 | B1 |
| 6631322 | Arthur et al. | Oct 2003 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 60801441 | May 2006 | US |
