Patent GB-222832-A (GB)
Title: Improvements relating to railway signalling apparatus
IPC: B61L23/16
Filed: 1924-06-27
Abstract: 222,832. Westinghouse Brake & Saxby Signal Co., Ltd., (Assignees of Young, H. S.). Oct. 6, 1923, [Convention date]. Electrical systems, automatic; lamp signals. -In light signals of the kind having units adapted' to be separately energized to indicate " proceed," " caution," and " danger " respectively, the units are also arranged to be energized in pairs to give signals intermediate in significance between those of the units concerned when used separately. Arrangement is made whereby, when a pair of units is being used, failure of a lamp causes a less permissive signal to be given. As described, this is effected by providing each unit with two lamps in parallel, and arranging that the more restrictive unit is in series with a fuse 6a and a relay L<A>, L<B> &c. controlling the circuit of the less restrictive .unit. Fall in current due to burning out of a lamp releases the relay armature, or rise in current due to short-circuit of a lamp blows the fuse, de-energizing the relay, and extinguishing the less restrictive unit. The track rails 1 are in insulated sections with each of which is associated a track battery E<a>, E<b> &c. in series with resistances 4, line transformer F<a>, F<b> &c., track relay T<A>, T<B> &c., relay L<A>, L<B> &c., pole-charging relay J<A>, J<B> &c., three-position relay K<A>, K<B> &c., and signal S<A>, S<B> &c. Each signal comprises units G, Y, Y', R which are green, yellow, yellow, and red respectively. Each three-position relay has two windings 29, 30, the former constantly supplied from the corresponding transformer, current to the latter being supplied from the transformer of the adjacent section and controlled by the relays of that section. A vehicle Z moving from left to right short circuits track relay T<D> and de-energizes pole-changing relay J<D>. The circuit of coil 30 of relay K<C> is thus broken, and the armatures of relay K<C> take the intermediate position shown. Relay J<C> is shown de-energized. Coil 30 of the relay K<B> is supplied from the transformer F<C> through wire 5, contact 32 of relay J<C>, contact 37 of relay T<C>, winding 30, contact 34 of relay T<C>, contact 31 of relay J<C>, and wire 11. Current of " reversed polarity is thus supplied, and the contacts 19, 26 of relay K<B> are moved to the left. When relay J<C> is energized, circuit for winding 30 is as above, except that the contacts of relay J<C> connect to supply current in the opposite or normal direction. Contacts 19, 26 are then moved to the right, as shown in relays K<A>, K<D>. As shown, relay TD is de-energized and unit R of signal SD is energized from transformer FD through relay L<C>, contact 8, unit R, to transformer. If either of the lamps in unit R be short-circuited or burnt out, contacts of relay L<D>. which are normally closed, are opened. When both lamps of unit R are lighted, a circuit is closed through unit Y from transformer Fd through wire 12, contacts 13 of relay TD, contact 15 of relay L<D>, unit Y, and transformer. When unit R is defective, contact 15 is opened, and the more permissive unit Y is 'extinguished. Unit Y' of signal S<C> is energized from transformer F<C> through relay L<C>, and contact 22. Coil 30 of relay K<C> is de-energized by contacts 34, 37 of relay T<D>, and circuit of relay J<C> is broken at the upper contact of relay R<C>. Coil 30 of relay K<B> thus receives current of " reversed polarity." Unit G of signal S<B> is energized from transformer Fb through wire 12, contacts 13, 24, 26, and the unit Y' is energized through relay L<B> and contacts 8, 19. If unit Y' fails, contact 24 opens and extinguishes unit G. Unit G of signal S<A> is energized through wire 12 and contacts 13, 26.