GB2331391A

GB2331391A - Railroad safety apparatus

Info

Publication number: GB2331391A
Application number: GB9720733A
Authority: GB
Inventors: James Ormond Beaumont
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-10-01
Filing date: 1997-10-01
Publication date: 1999-05-19
Also published as: GB9720733D0

Abstract

An apparatus is provided to wam of imminent train collision or derailment by means of physically examining the space and track ahead of a train. A specific example is shown wherein a precursor vehicle is controlled to run ahead of said train by a variable distance equal to the current safe stopping distance of said train, testing the track and probing the adjacent space for obstacles. Appropriate "all clear", "caution", or "stop" signals are provided in the locomotive.

Description

2331391 RAILROAD SAFETY APPARATUS This invention relates to an apparatus

for providing warning of an impending railroad collision or derailment in time to allow safe stopping of the train before such mishap can occur.

Current practice involves the use of signals, typically based upon the conduction of an electrical current through the rails of one or more blocks of track ahead of the block the train is in. If this current is short-circuited by another train, or interrupted by an open switch or broken rail, an appropriate signal is transmitted to track-side signals andlor directly to the locomotive cab, indicating all clear, various degrees of caution, or stop. Such signals fail to warn of any obstacle on, above, or adjacent to the track which does not electrically short the rails. Similarly, such signals fail to warn of any track defect or switch setting which does not interrupt the track Is electrical continuity.

According to the present invention, which provides warning of impending danger by physically probing track space ahead of the train, there is provided: a precursor robot vehicle, an obstacle sensor, two distance and speed sensing means, a data link, and two data processing means.

A specific embodiment of the invention will now he described by way of example with reference to the accompanying block diagram, Figure 1.

Referring to the diagram, the data processors consist of digital computers with analog/digital input-output capability, data processor 1 also having display and audio alarm capabilities. The distance and speed measuring equipment consists of a ranging transmit/receive unit, a transponder unit, a compass, and two wheel-connected speedometerlodometer units, the speedometerlodometer in the precursor vehicle being connected to a non-driven wheel. The "2- data link consists of a pair of radio transmit/receive units. The obstacle sensor consists of a loop of wire surrounding a rectangular frame which is perpendicular to the track direction, with height and width equal to those of the train.

In order to detect imminent collision or derailment, the apparatus functions in the following manner. From the locomotive speed, obtained from speedometer 1, data processor 1 determines the safe stopping distance of the train, compares this with the distance to the precursor vehicle, obtained from the distance and speed measuring equipment, and calculates the desired speed of said precursor vehicle to maintain its position at a safe stopping distance ahead of the train. This speed information is transmitted, via the data link, to data processor 2, which compares said desired speed with the vehicle's actual speed, obtained from speedometer 2, and generates appropriate throttle and brake control signals. The vehicle speed, direction, and obstacle signals are continuosly transmitted, via the data link, back to data processor 1.

In the event that the precursor vehicle strikes an obstacle on the track it may be so damaged as not to transmit a signal back to data processor 1 or it may merely be stopped more-or-less intact and transmit back a zero velocity signal. In the event the obstacle sensor strikes an obstacle above or beside the track, continuity of the wire loop will be broken and a corresponding signal will be transmitted back to data processor 1. In the event of a derailment any possible combination of the above may occur.

Any one of the above conditions, viz., no signal, zero velocity signal, or obstacle signal, will cause data processor 1 to issue an immediate stop alarm. Less threatening conditions, viz., inability to maintain the desired vehicle position or speed, will cause data processor 1 to generate appropriate caution signals.

In order to use this apparatus in conjunction with existing conventional signalling systems, the wheels on opposite sides of the precursor vehicle are electrically insulated one from another to avoid interference with said signalling system.

The meaningful distance from the locomotive to the precursor vehicle is as measured along the track. If the track is straight, this distance is measured correctly by time-of-flight range measurement by the transmit/receive unit and the transponder unit. However, if the track is significantly curved this straight-line range is not a good approximation to the along-track distance. The along-track distance may be determined by subtracting the reading of the odometerin the locomotive from thatin the precursor vehicle, but this determination is subject to long-term cumulative error due to inaccuracy of the odometer units. According to the present invention, the correct along-track distance is determined as follows: Data processor 1, in the locomotive, continuously receives inputs including the straight-line range distance from locomotive to precursor vehicle, speed and distance travelled by the precursor vehicle, speed and distance travelled by the locomotive, and directional heading of the precursor vehicle. From the history of the precursor vehicle speed and heading, data processor 1 calculates the departure by which the vehicle is left or right of the straight line extension of the track at the locomotive's position. If this departure is less than a preset fraction of the straight-line range distance, the track is deemed to be straight, said range distance is used as the measure of locomotive to precursor vehicle separation and is also used to correct cumulative odometer errors and to recalibrate speedometer 2 in the precursor vehicle. If said departure is greater than said preset fraction the track is deemed to be significantly curved and the difference of odometer readings is used as the measure of separation.

Claims

1. An apparatus constructed and arranged for detecting and warning of imminent collision or derailment of a railroad train comprising a probe for physically examining the space ahead of said train for obstacles and rail defects.

2. An apparatus as claimed in Claim 1, wherein said probe comprises a precursor vehicle running ahead of the train.

3. An apparatus as claimed in Claim 2, wherein said precursor vehicle is controlled to run ahead of the train by a track distance equal to the safe stopping distance of the train.

4. An apparatus as claimed in Claim 3, wherein said safe stopping distance is determined by computer algorithm from the measured train speed.

5. An apparatus as claimed in any of Claims 3-4, wherein said precursor vehicle is controlled to said track distance by comparing said safe stopping distance with the actual track distance between train and precursor vehicle and adjusting precursor vehicle throttle or brake accordingly.

6. An apparatus as claimed in Claim 5, wherein said actual track distance is determined by straight-line range measurement in conditions of straight track and by relative odometer readings in conditions of significantly curved track.

7. An apparatus as claimed in Claim 6, wherein the straight or curved condition of track is determined by calculation from the recent history of precursor vehicle speed and directional heading.

8. An apparatus as claimed in Claim 6, wherein said straight-line range measurements are used in conditions of straight track to reset the relative odometer readings and to reeMibrate the speed input to one or the other odometer.

9. An apparatus as claimed in any of Claims 2-8, wherein said precursor vehicle is fitted with obstacle sensing means for detecting any obstacle on, above, or beside the track within the space of the height and width of the train.

10. An apparatus as claimed in Claim 9, wherein said obstacle sensing means comprises a loop of wire surrounding a rectangular frame, perpendicular to the track direction, with width and height equal to those of the train.

11. An apparatus as claimed in any of Claims 1-10, wherein a stop alarm, caution signal, or all clear signal is generated as appropriate.

12. An apparatus as claimed in any of claims 2-11, wherein the wheels on opposite sides of the precursor vehicle are electrically insulated from each other.

13. A railroad imminent collision or derailment warning apparatus substantially as described herein with reference to Figure 1 of the accompanying drawing.