System for selectively determining the location of a railway car moving along a railway track

• US 4,151,969 A
• Filed: 09/12/1977
• Issued: 05/01/1979
• Est. Priority Date: 09/12/1977
• Status: Expired due to Term

• Current Assignee: Southern Railway
• Original Assignee: Southern Railway
• Inventors: Wood, Robert E.
• Primary Examiner(s): Kunin, Stephen G.
• Application Number:
  US05/832,617
• Time in Patent Office: 596 Days
• Field of Search: 73/597, 73/628, 104/26, 246/30, 246/122 R, 246/125, 246/128, 246/130, 246/167 R, 246/167 D, 246/182 R, 246/182 A, 246/182 BH, 246/182 C, 246/187 C, 324/83 D, 324/171
• US Class Current: 246/122.00R
• CPC Class Codes: B61L 17/00 Switching systems for classification yards

Abstract

The velocity of a railway car travelling along a particular track can be determined by measuring the distance travelled by the car during a predetermined time interval. This distance travelled is measured by determining the location of the car with respect to a fixed point on the track at two different points of time. The determination of the location, in turn, is found by measuring the time period that it takes an electric signal applied at a fixed signal generating point to travel along the railway track and, once reaching the car, to be reflected back along the track to the signal generating point. By measuring the time delay between the applied signal and the reflected signal, the distance between the application point and the closest railway car on the track can be measured.

Claims

1. A system for measuring the velocity of a car moving along a railway track comprising:

means for determining the location of the car on the railway track including;

pulse generating means capable of being coupled to a first rail of the track for transmitting a pulse signal along such rail, whereby such pulse signal travels along the first rail until it reaches the location of a railway car on the track where the rear wheels and axle of such car electrically couple the first rail and the second rail of the track;

the pulse signal is then transferred from the first rail to the second rail back towards the point at which the pulse signal originated;

pulse receiving means for receiving the pulse signal supplied to the first rail at the same time that such pulse signal is applied and also adapted to be coupled to the second rail at a point corresponding to the location at which the pulse generating means is coupled to the first rail so that said pulse receiving means receives the pulse signal back along the second rail; and

, measuring the time delay between the application of the pulse signal to the first rail and the receipt of the pulse signal reflected back along the second rail and in response to such measurement providing an output signal indicative of the location of the wheels and the axle of the car that acted as the electrical shunt for the system for the first and second rails of the railway track, such indication being indicative of the location of the car on the railway track closest to the point at which the pulse signal is supplied to the first rail of the railway track;

said means for determining the location of the car making at least two such measurements with a predetermined time interval between such measurement;

means for determining the distance traveled by the car during said time interval in response to the output signals received from the means for determining the location of the car; and

,

means for determining the velocity of the car based upon the distance traveled by the car during said time interval.

2. A system for determining the velocity of the most recent car entering and moving along each storage track of a railway classification yard having a plurality of storage tracks where the rear axle and wheels of such car electrically shunt the two rails of the respective storage track, the system comprising:

means for determining the location of the most recent car entering each storage track at least twice with a predetermined interval between each such measurement, such means including;

signal supply means for supplying a pulse signal to the first rail of each of the storage tracks, such pulse being transmitted along the first rail until it reaches the shunt formed through the rear wheels and axle of the last car in the storage track, such pulse signal then being transferred through the shunt to the second rail of the storage track and transmitted along the second rail back towards the initiation point of the storage track, measuring means for measuring the time delay between application of the pulse signal to the first rail of one of the tracks and receipt of the pulse signal reflected back along the corresponding second rail of the same track and providing an output signal indicative of the location of the last car on the storage track selected by said track selecting means based upon such time delay; and

, track selecting means for selectively coupling the pulse signal supply to the first rail of one of the tracks and the pulse signal reflected back along the corresponding second rail of the same track to said measuring means;

means for determining the distance traveled by the car during said time interval in response to the output of the means for determining the location of the car; and

,

means for determining the velocity of the car based upon the distance traveled by the car during said time interval.

3. A system as defined in claim 2 wherein:

said pulse signal supply means provides a series of pulses to the first rail of each of the tracks; and

said track selecting means includes multiplexing means for sequentially coupling to said measuring means the pulse signal supplied to the first rail of a selected track and the reflected pulse signals from the second rail of the same track.

4. A system for determining the location of a car on a railway track comprising:

pulse generating means capable of being coupled to a first rail of the track for transmitting a pulse signal along such rail, whereby such pulse signal travels along the first rail until it reaches the location of a railway car on the track where the rear wheels and axle of such car electrically couple the first rail and the second rail of the track, the pulse signal is then transferred from the first rail to the second rail and travels in the second rail back towards the point from which the pulse signal originated;

pulse receiving means for receiving the pulse signal supplied to the first rail at the same time that such pulse signal is applied and also adapted to be coupled to the second rail at a point corresponding to the location at which the pulse generating means is coupled to the first rail so that said pulse receiving means receives the pulse signal reflected back along the second rail; and

,

measuring means coupled to said pulse receiving means for measuring the time delay between receipt of the pulse signal supplied to the first rail and receipt of the pulse signal reflected back along the second rail and in response to such measurement providing an output signal indicative of the location of the wheels and axle of the car that acted as the electrical shunt for the system between the first and second rails of the railway track, such indication being indicative of the location of the car on the railway track closest to the point at which the pulse signal is supplied to the first rail of the railway track.

5. A system for determining the location of the last car in each storage track of a railway classification yard having a plurality of storage tracks where the rear axle and wheels of such cars electrically shunt the two rails of the storage track, the system comprising:

signal supply means for supplying a pulse signal to the first rail of each of the storage tracks, such pulse signal being transmitted along the first rail until it reaches the shunt formed through the rear wheels and axle of the last car in the storage track, such pulse signal then being transferred through the shunt to the second rail of the storage track and transmitted along the second rail back towards the initiation point of the storage track;

measuring means for measuring the time delay between application of the pulse signal to the first rail of one of the tracks and receipt of the pulse signal reflected back along the corresponding second rail of the same track and providing an output signal indicative of the location of the last car on the storage track selected by said track selecting means based upon such time delay; and

,

track selecting means for selectively coupling the pulse signal supplied to the first rail of one of the tracks and the pulse signal reflected back along the corresponding second rail of the same track to said measuring means.

6. A system as defined in claim 5 wherein:

said pulse signal supply means provides a series of pulses to the first rail of each of the tracks; and

said track selecting means includes multiplexing means for sequentially coupling to said measuring means the pulse signal supplied to the first rail of a selected track and the reflected pulse signals from the second rail of the same track.

7. In a railway classification yard having a plurality of storage tracks, each of the storage tracks having first and second rails, a system for determining the distance that the next car entering a particular storage track must travel before coupling with the last car that entered such track, such distance to coupling being determined by measuring the distance between the last car on each storage track and a location near the entrance of such storage track, the system comprising:

pulse signal generating means for supplying a pulse signal to the first rail of each of the storage tracks at a first location, such pulse signal being transmitted along the first rail until such pulse signal reaches the rear wheels and axle of the last car in each respective storage track which electrically shunt the first and second rails, the pulse signal then being transferred to the second rail through such shunt and the signal being transmitted in the second rail back towards the entrance of the respective storage track;

measuring means for measuring the time delay between the application of the pulse signal to the first rail of one of the tracks ad the receipt of the pulse signal reflected back along the corresponding second rail of the same track and said measuring means providing an output signal indicative of such time delay;

multiplexing means for selectively coupling said measuring means to the first and second rail of a selected track; and

,

indicating means coupled to receive the output signal of said measuring means and in response thereto providing a signal indicative of the location of the last car on the storage track selected by said multiplexing means.

8. A system for determining the velocity of the most recent car entering and moving along each storage track of a railway classification yard having a plurality of storage tracks where the rear axle and wheels of such car electrically shunt the two rails of the respective storage track, the system comprising:

means for determining the location of the most recent car entering each storage track at least twice with a predetermined interval between each such measurement, such means including;

signal supply means for supplying a signal to the first rail of each of the storage tracks, such signal being transmitted along the first rail until it reaches the shunt formed through the rear wheels and axle of the last car in the storage track, such signal then being transferred through the shunt to the second rail of the storage track and transmitted along the second rail back towards the initiation point of the storage track, measuring means for measuring the time delay between application of the signal to the first rail of one of the tracks and receipt of the signal reflected back along the corresponding second rail of the same track and providing an output signal indicative of the location of the last car on the storage track selected by said track selecting means based upon such time delay; and

, track selecting means for selectively coupling the signal supplied to the first rail of one of the tracks and the signal reflected back along the corresponding second rail of the same track to said measuring means;

said measuring means including;

first signal generating means for generating a first impulse signal in response to the leading edge of the signal supplied to the first rail;

second signal in response to the leading edge of the reflected signal received from the second rail; and

comparator means for generating an output signal based upon the time between the first impulse signal and the second impulse signal;

means for determining the distance traveled by the car during said time interval in response to the output of the means for determining the location of the car; and

,

means for determining the velocity of the car based upon the distance traveled by the car during said time interval.

9. A system as defined in claim 8 wherein the output signal generated by said comparator means is an analogue signal and said measuring means further includes an analogue-to-digital convertor coupled to receive the output signal from said comparator means and in response thereto producing a digital output signal.

10. A system as defined in claim 9 further comprising a control means, said control means including means for initiating operation of said signal supply means and indicating means coupled to said converter means to receive the digital output signal and in response to such signal providing information about the location of the last car in each storage track.

11. A system for determining the location of the last car in each storage track of a railway classification yard having a plurality of storage tracks where the rear axle and wheels of such cars electrically shunt the two rails of the storage track, the system comprising;

signal supply means for supplying a series of signals to the first rail of each of the storage tracks, such signal being transmitted along the first rail until it reaches the shunt formed through the rear wheels and axle of the last car in the storage track, such signal then being transferred through the shunt to the second rail of the storage track and transmitted along the second rail back towards the initiation point of the storage track;

measuring means for measuring the time delay between application of the signal to the first rail of one of the tracks and receipt of the signal reflected back along the corresponding second rail of the same track and providing an output signal indicative of the location of the last car on the storage track selected by said track selecting means based upon such time delay;

said measuring means including first signal generating means for generating a first impulse signal in response to the leading edge of the signal supplied to the first rail;

second signal generating means for generating a second impulse signal in response to the leading edge of the reflected signal received from the second rail; and

comparator means for generating an output signal based upon the time between the first impulse signal and the second impulse signal; and

,

track selecting means including multiplexing means for sequentially coupling to said measuring means the signal supplied to the first rail of a selected track and the reflected signals from the second rail of the same track.

12. A system as defined in claim 11 wherein the output signal generated by said comparator means is an analogue signal and said measuring means further includes an analogue-to-digital converter coupled to receive the output signal from said comparator means and in response thereto producing a digital output signal.

13. A system as defined in claim 12 further comprising a control means, said control means including means for initiating operation of said signal supply means and indicating means coupled to said converter means to receive the digital output signal and in response to such signal providing information about the location of the last car in each storage track.