Patent GB-371921-A (GB)
Title: Improvements relating to railway interlocking installations
IPC: B61L19/06
Filed: 1931-01-26
Abstract: 371,921. Railway signalling systems. STOLTZ, C. F., 6636, Nokomis Avenue, Cincinnati, Ohio, U.S.A. Jan. 26, 1931, No. 2572. [Class 105.] In a railway system in which trains move in both directions over a railway track, an electric interlocking installation to supervise a certain stretch of track comprising a plurality of block sections includes a group of relays (directional stick route relays) which are operated when the signal governing entry into the stretch in the pertaining direction of. movement is manually cleared and serve to prevent a route in the opposite direction being set up but permit the rear sections to be released as the train passes out of each rear section. The Figures show the arrangement for a stretch of track comprising approach sections T<0>, T<8>, sections T<2>, T<6> with turn-out points, and an intermediate section T<4>. This 'stretch of track adjoins on the right-hand side an automatically signalled stretch. The interlocking installation includes a miniature diagrammatic representation t<0> .. t<8> of the sections TO .. T<8>, with the signal and points operating levers located adjacent the corresponding symbols. Approach locking is effected by means of thermal devices and associated stick relays such as device TH<9> and relay THS<9> controlled by a track repeater relay TR<8>. The setting up of an opposite direction route is prevented by the two groups of directional stick route relays ES<2>.., WS<2> ... The signals S<3> .. are operated by relays HR3 .. which are controlled by points repeater relays SSa .. , by conflicting signal lever relays such as R<5>, and by the directional relays such as WS<4>. The apparatus is shown in the normal condition. When a west-bound train enters the approach section T<8> the operator is notified (by means not shown) and if he wishes to send it on the turn-out he operates the points lever SMLb which in its passage temporarily closes a contact 102 to energize a slow release relay LRb whereby the points motor is operated to reverse the points ; the motor circuit is from the negative pole B - over points lever contact 103 at reverse (dotted position), front contact 115 of the slow release relay LRb, motor SMb and front contact 118 to mid-point C of the electric supply. The operator now clears the signal S<9> by operating the signal lever SL<9> to energize the relay R<9> which at its front contacts 124, 127 completes the circuit to relay HR<9> from B + over reverse contact 122 of points repeater relay SSb. The front contact 128 of relay HR<9> energizes the yellow lamp Y of signal S<9>. The back contact 50 of relay HR<9> is now open and de-energizes thermal relay THS<9>, the contact 57 of which opens to de-energize directional relay WS<6> the open contact 105 of which now prevents operation of the points operating relay LRb even if the points lever SMLb be restored. When the train enters section T<6> the track repeater relay TR<6> and track repeater stick relay TRS<6> are de-energized, the contact 107 of the latter opening another point in the circuit to the points operating relay LRb. When the train has left the turn-out and the signal lever SL<9> is restored, the apparatus resumes its normal condition and the points lever SMLb can be returned to normal and temporarily energize the relay LRb whereby the points are restored to normal. If the operator by restoring the signal lever SL<9> puts the signal S<9> to danger in the face of an approaching train in section T<8> the thermal relay THS<9> is not energized until after an interval determined by the time required for the heating element TH<9> to effect the closure of contact 183 in the pick-up circuit of thermal relay THS<9> from back contact 50 of relay HR<9>. The points could not therefore be altered until this interval had elapsed which is sufficient for the train to have been pulled up at signal S<9> or, if the change of signal was given too late, to have entered section T<6> and thereby opened the contact 107 of track repeater stick relay TRS<6> in the circuit to the points operating relay LRb, in which case the points cannot be altered till the train has left section T<6>. To clear the signal S<3> for an East-bound train the signal lever SL<3> is operated to energize the relay R<3> the front contacts 148, 143 of which complete the circuit of relay HR<3> from B + over front contact 136 of directional relay WS<4>, back contact 139 of signal relay R<5>, and normal contact 141 of points repeater relay SSa. Front contact 150 of relay HR<3> extinguishes the red lamp R and lights the yellow lamp Y of signal S<3> while the opening of contact 10 of relay HR<3> de-energizes thermal relay THS<3> the contact 8 of which opens to de-energize the directional relay ES<2> which in turn opens its contact 22 to de-energize directional relay ES<4>. Accordingly if the operator were now to attempt to clear signal S<9> by operating the signal lever SL<9> the circuit to relay HR<9> would be open at the dropped contact 151 of directional relay ES<4>. The circuit to relay HR<9>, with the points normal, i from B +, front contact 151 of relay ES<4>, back contact 154 of conflicting signal relay R<7>, contact 157 of time element TEC, normal contact 122 of points repeater relay SSb, and front contacts 124, 127 of signal relay R<9>. If a West-bound train is to change engines the train is stopped at signal S<5> which is then cleared by operating the lever SL<5> to allow the uncoupled engine to go forward. A fresh engine must then be backed on past signal S<3> which cannot, however, be cleared by operating the lever SL3 since the train has already deenergized relay WS4, the contact 136 of which is therefore dropped and breaks the circuit over which relay HR<3> would normally be energized. A push-button PB, however, permits the signal S3 to be cleared ; a relay PBS<4> is picked up on depression of the push-button PB and then held over the back contact 136 of relay WS<4> and its own stick contact 176. On operating the signal lever SL<3> the signal operating relay HR<3> will now be energized over a circuit from B +, front contact 180 of push-button relay PBS<4>, back contact 139 of conflicting signal relay R<5>, normal contact 141 of points repeater relay SSa, and front contacts 143, 148 of relay R<3>. The signal S' governing the entrance to the automatically signalled stretch is controlled by the section ahead through a relay DR<7> to give a full clear G or a caution Y signal when the lever SL<7> is operated. Further the signal S<7> is put to danger on the entrance of a train into section T<6> and the lever SL7 must be restored before another signal can be given ; this is effected by the signal operating relay HR<7> being energized over a front contact, of the track repeater stick relay TRS<6> which can only be picked up over a back contact of the relay R<7> and which is picked and held only when the track section T<6> is clear to allow the track repeater relay TR<6> to close its front contact.