AU598788B2 - Positive route identification - Google Patents

Description

z i i d::I ~,i1 598788.o COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Application Number: Lodged: 691J1 /07 Class Int. Class Complete Specification Lodged: Accepted: Published: Priority: 0 R'elated Art: (tPCWT n.i-

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0* S* 0 Nameof Applicant: WESTINGHOUSE BRAKE AND SIGNAL COMPANY LIMITED o iaPew Hill, Chippenham, Wiltshire, United Kingdom Address of Applicant: *tu MICHAEL JOHN

BEASLEY

Actual Invenor: ***lress for Service: EDWD. WATERS SONS, r d o r50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: POSITIVE ROUTE IDENTIFICATION The following statement is a full description of this invention, including the best method of performing it known to us 1 1~ i, -1 a- POSITIVE ROUTE IDENTIFICATION The present invention relates to an arrangement for positively identifying the route taken by a railway vehicle. The invention is particularly useful in driverless trains although this is not its only application.

If a train may be switched on to alternate routes, or directed on to alternate paths on the same route e.g. into a passing loop, and be required to pull up to one of several station platforms, it is important that the train control equipment should know the exact position. of the train in order to calculate or select an appropriate braking or driving profile. For 15 example: on the approach to a station with several platforms, to any one of which the train may be .r switched, each platform may require a different braking St' profile for the train to stop at that platform. In i such a situation, an embodiment of the invention has for one of its objects to provide the necessary cues to the train so that the control equipment will select the tCt correct braking profile.

t c r According to the present invention there is

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provided an arrangement for positive route 25 identification by which a railway vehicle is able to

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c C Cpositively identify its route, wherein each of a plurality of alternative paths of a permanent way is t c E defined by track circuit sections the track circuit Sfrequencies of which are arranged in a prede'termined sequence and a railway vehicle constrained to travel on said permanent way has: means for sensing each such track circuit frequency to produce a sensed signal; means for measuring distance travelled from an initial point; means in which is stored information describing 35 each path in terms of the frequencies of its track S/r\ circuit sections and distances of its track circuit -0 -2sections from said point; and means for comparing a sensed signal at a measured distance with said stored information whereby to identify the path over which the vehicle is travelling, wherein at a predetermined distance from said initial point, the track circuit sections of said alternative paths have different track circuit frequencies.

The invention and how it may be carried into practice will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a diagram of a station approach having three alternative routes leading to separate platforms; and S Fig. 2 shows a block diagram of an automatic train 15 operating system employing this invention.

Referring to Fig. 1, the arrangement of track I 1* ,circuit frequencies F is shown in part of a track St", layout approaching a station or depot. The two tracks between stations are labelled conventionally "UP line" and "DOWN line" with the normal direction of traffic on each shown by the accompanying arrow,. The two tracks S"r' are interconnected with three platform approach tracks tlabelled A, B and C.

The system employs a total of seven track circuit 25 carrier frequencies which are-a-llocated as shown in Fig. 1. On the "DOWN line" leading to A, a train travelling in the direction of the corresponding arrow w :will encounter a repeated sequence of frequencies F2, S. FS, F7. On the "UP line" leading to B, a train travelling in the direction indicated by the corresponding arrow will encounter a repeated sequence of frequencies F1, F3, F6. On the track leading to C, the first mentioned sequence of F2, F5, F7 will be repeated.

The interconnecting sections of track are 1 I' identified with a track circuit carrier frequency F4.

S* This frequency -3is reserved for connecting sections of track, crossovers etc. so that i t is only detected by a train during the course of changing from one track to another.

A train at position S on track A has just entered a track section having the characteristic frequency F7.

When the train has travelled a distance x along track A, without diversion, it will be passing through the next track section,having characteristic frequency F2. After a distance 2x from position S along track A it is within a section identified by frequency and after distance 3x it will again occupy a section identified by frequency F7.

Assuming that at point P1 the train is diverted, then at the end of distance x it will occupy a section zidentified by characteristic frequency F4. At point P2 the train may be either switched on to track B or switched on to a further interconnecting section taking, it towards point P3 on track C. If it is diverted on to track B, then after a distance 2x the train is within a track section identified by the characteristic frequency F6, and after a distance 3x it occupies a section having characteristic frequency F3.

However, if at point P2 the train is diverted towards track C after travelling a distance 2x, it still occupies a track section identified by characteristic frequency F4, and after travelling a distance 3x is then within a section identified by frequency F2.

Consider, therefore, a train equipped with means for sensing the track circuit frequency of track sections over which it passes. In the first alternative it senses the frequency sequence F2, F5, F7, F2 etc. and receives no other frequency. In the second alternative it senses the frequencies F2, F5, F7, F4, F6, F3, Fl, and in the third alternative it senses the sequence F2, F5, F7, F4,F4,F2,F.. Thus, means capable of discriminating between these frequency ,It -4sequences is able to determine whether the train, having travelled a distance 3x from point S, is then on track A, track B or track C.

Referring now to Fig. 2, this shows a block diagram of an automatic train operating system employing an embodiment of the invention. The track circuit signals are carried by track running rails indicated at 20. The train is equipped with sensing coils 21 positioned close to the track rails and inductively coupled with the raiils in order to provide an output at 22 connected to automatic train protection equipment 23 on the train.

A.T.P. equipment 23 could be of a form known in the art see for example British Patent Specifications 15 Nos. 2159311 and 2017991. As is known from the prior art, such A.T.P. equipment performs a fail-safe safety function according to which the train's brakes are applied if, for example, no track circuit signal is detected, or the measured speed of the train S 20 exceeds the maximum speed limit indicated by a coded modulation signal carried by the track circuit signal.

The A.T.P. equipment 23 provides an output 24, consisting of the characteristic track circuit frequency, which is connected to -automatic train operating equipment 25 which, among other things, controls the brakes and the drive motors of the train.

A.T.O. systems are well known in the art and it is not proposed to describe here their construction C. C, or detailed operation. It is sufficient to know that such a system draws upon several sources of information and compares variable parameters either one with the other, or with fixed stored values,to determine acceleration, deceleration and velocity values.

One of the sources of information for the A.T.O.

equipment 25 is a geographical information store Sgenerally indicated at 26 in Fig. 2. This comprises an electronic store of information such as track circuit i

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frequency sequences, location code words, distance between identifiable points, gradient information etc.

This information is indexed in the memory so that it may be read by the A.T.O. equipment sequentially as the train moves along a route.

A distance measuring means in the form of a tachometer or odometer 27 is also connected to the A.T.O. equipment 25 to supply a measurement of distance travelled by the train. This distance is used by the A.T.O. equipment 25 to address the geographical information store 26 in order to read from it corresponding information concerning the position of the train and the route being traversed.

The A.T.O. equipment 25 may be set to update its operating information after each distance x travelled by the train (see Fig. If in travelling the distance x from its last information update the train has been diverted from say, track A at point P1 in Fig. 1, the information read from memory 26 will indicate the alternative possibilities, for example that the track circuit shall have a frequency of either F4 or F2. The A.T.O. equipment is then able to determine, if the received track signal frequency is F4, that the train has been diverted at point P1 towards P2. After a further distance x, by comparing the then received track circuit frequency, it can further determine if the train has been switched on to track B, when. the track circuit frequency CC will be F6,or if the train has been further switched 30 towards point P3 and track C, when the track circuit.

signal will have frequency F4. A subsequent check after distance 3x will confirm whether the train is travelling on track-B and receiving a track circuit signal having a frequency F3, or whether it is on track C and receiving a track circuit signal having a frequency F2.

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[lLrrr -6- In one form of the invention, the route detecting equipment is arranged to be operatively responsive to reception of the intermediate section frequencies F4 only, and is not normally stimulated by the normal fixed track circuit frequency sequences.

In normal track layouts,the track circuit signals are carried by the running rails except at cross-overs, intersections etc. where the track circuit signals are carried by signal conducting loops laid in the track bed. A first loop extends along the normal direction of track and carries the expected straight ahead signal having a carrier frequency in the expected sequence. A second loop is also laid in the track bed extending for a short distance along the straight track, up to the commencement of the cross-over track section, and then following the branching t or interconnecting section. If the track points are set to divert a train, then the second branch I loop is energised and carries a signal having carrier S 20 frequency F4. If the track points are set straight ahead, then the second loop is not energised but the first loop carries a signal having a carrier signal frequency as determined by the sequence on that line.

The commencement of an interconnecting section is accurately marked at a fixed, predetermined point by the commencement of the track section signal loop which, thus, may serve as the reference marker point or initial point.

Claims (2)

1. An arrangement for positive route identification by which a railway vehicle is able to positively identify its route, wherein each of a plurality of alternative paths of a permanent way is defined by track circuit sections the track circuit frequencies of which are arranged in a predetermined sequence and a railway vehicle constrained to travel on said permanent way has: means for sensing each such track circuit frequency to produce a sensed signal; means for measuring distance travelled from an initial c e point; means in which is stored information describing each path in terms of the frequencies of its track circuit sections and distances of its track circuit sections from said point; and means for comparing a sensed signal at a measured distance with said stored A information whereby to identify the path over which the vehicle is travelling, wherein at a predetermined distance from said initial point, the track circuit sections of said alternative paths have different track circuit frequencies.

2. An arrangement for positive route ftu identification substantially'as described with reference to the accompanying drawings. DATED this 9th day of April 1990 WESTINGHOUSE BRAKE AND SIGNAL COMPANY LIMITED X' WATER~1ARK PATENT TRADEMARK ATTORNEYS 2,1THE ATRIUM S1- /290 BURWOOD ROAD HAWTORN VICTORIA 3122 o/ AUSTRALIA .y tit 1