Patent GB-359499-A (GB)
Title: Improvements in or relating to train control systems
IPC: B61L3/12
Filed: 1930-07-23
Abstract: 359,499. Train control and cab signalling systems. ASSOCIATED TELEPHONE & TELEGRAPH CO., 1033, West Van Buren Street, Chicago, U.S.A. July 23, 1930, No. 22236. Convention date, Sept. 23, 1929. [Glass 105.] In a train control and cab signalling system of the magnetic induction type the track elements comprise magnet apparatus controlled in accordance with the state of track occupation and direction of travel of the train so that the appropriate signalling devices are operated. The system is used for single line working. Fig. 1 shows the locomotive receiver apparatus and Figs. 2 to 4, which are to be placed in line, show the track arrangements. Track relays such as T<1>, T8 are placed at each end of double track-sections such as BC-CD to control pole-changing relays such as P<1>, P<8> by which current of normal or reverse polarity is supplied, across track relay contacts, to polarized relays of the adjacent sections such as L<6> and I<6> which respectively control wayside lamp signals such as S<6> and trackway electromagnets M<6>, the latter serving to actuate the apparatus on the locomotive. The Figures show the normal position of the apparatus, all the track relays being energized so that the pole-changing relays, which are each energized over contacts of the two track relays of their double track-section, lift their contacts and apply normal current to the line relays such as L<6> at the distant ends of the adjacent double track-sections so that the lamps G of the wayside signals are lit over the normal contacts of these last relays to show " clear." The track electromagnets are only energized on the approach of a train as the circuits of their control relays include a back contact of a track relay. An East-bound train entering the half-section BC causes the contacts of track relay T<1> to open the circuits of pole-changing relays P<1>, P<8> and to open at contact 34 a point in the circuit to the line relay L<8> which drops a contact to light a lamp R of the West-bound signal S<8> to show " danger " ; the circuit to the line relay L<8> is from battery 88, wire 33, contact 34, wire 35, contact 36, wire 37, relay L<8>, wire 38, and common return wire 30. The dropped contacts of pole-changing relay P<8> cause reverse current to be applied to the line relay L<6> at the distant end of the forward adjacent double section DE-EF so that the polarized armature moves to the right to light lamp Y of Westbound wayside signal 8<6> to show " caution " ; the dropped contacts of relay P<1> similarly actuate a caution East-bound signal (not shown) at the distant end of the rear adjacent double-section. When the train enters the half-section CD the track relay T<8> is de-energized and drops its armatures, of which 28, 56 maintain the pole-changing relays P<1>, P<8> de-energized to maintain the caution signals ; armature 57 opens the circuit of the line relay L<8> (not shown) of East-bound signal S<1> which continues to give a danger signal at lamp R, having been opened by a similar armature of track relay T<1>; the dropped armature 36 maintains relay L<1> de-energized and therefore the signal S<8> continues to show danger; the dropped armature 58 however causes relay I<3> to be energized by normal current from a battery 33, Fig. 3, over wire 75, contact 74, wire 73, contact 72, wire 69, the back contact 58, relay I<3>, wire 67, and common wire 30. The relay I<3> when energized normally has its polarized armatures at the right and therefore the track electromagnet M<3> is energized nor. mally to give North poles at the outside and a South pole at the middle. The relay I<3> has an upper armature acting as a stick circuit, so long as the back contact 58 of relay T<8> is made, to maintain the energization after the contact 72 of track relay T<3> drops. The electromagnet is within a distance equal to the shortest train length and is therefore in an effective state when the locomotive passes over. When the train leaves section BC-CD the signal S<1> shows " caution," the lamp Y being lit since the line relay L<1> (not shown) will be reversely energized due to pole-changing relay P<3> having been de-energized on the entry of the train into section DE-EF. Signal 8<4> similarly shows " caution." Signals S3, S<6> show danger in the manner already described for signals S<1>, S<8>. The train when in any double-section DE-EF puts the signals S<3>, S<6> thereof to " danger " for following and approaching trains and the signals S\ S<4> of the adjacent double-sections to " caution." With a train standing in section HI, an overtaking train in section EF and entering section FG will pass over the electromagnet M<5> energized in the reverse condition since pole-changing relay P7 is dropped due to the train in section HI having deenergized track relay T7. The action on the train apparatus will now be considered. The train apparatus, Fig. 1, comprises magnetic collector plates 105<1> .. 105<6> which co-operate with polarized armatures 107<1> .. 107<4> which are moved to the inner positions shown when the outer collector plates move over North poles. When therefore the train enters section FG and passes over the track permanent magnet PM<3>, two of the armatures 1072, 107<4> or 107<1>, 107<3> (depending on the polarity of the permanent magnet) move to the outer position and when the reversely energized electromagnet M5 with outer South poles is passed all the armatures 107<1> .. 1074 go to the outer position to light a caution lamp Y and apply the brakes by deenergizing an electropneumatic brake valve EPV. A pushbutton PB by energizing magnets 108 to move the armatures 107<3>,107<4> to the inner position permits cancelling of the braking. When the train enters the occupied section HI the electromagnet M<7> is not energized since the circuit of the relay I<7> is open at contact 102. The train armatures are therefore put out of phase by the track permanent magnet and cause a brake application to be initiated; if the cancelling button PB is operated a red lamp R is lit over a dropped contact of a dual relay 110 which is energized when either the caution Y or clear lamp G is lit. Specification 355,337 is referred to.