Patent GB-502085-A (GB)
Title: Improvements in or relating to railway signalling systems
IPC: B61L7/08
Filed: 1937-08-10
Abstract: 502,085. Railway signalling control apparatus. STANDARD TELEPHONES & CABLES, Ltd., and GRIFFITHS, J. B. Aug. 10, 1937, No. 22006. [Class 105] [Also in Group XXXVIII] Route-setting uquipment situated at away station and of the kind normally responsive to manual operation of route levers, keys, or the like and having electric interlocking between routes is remotely operated from a distant control panel provided with route levers, keys, or the like which transmit a signal to operate signal-receiving equipment at the way station whereby the route-setting equipment is operated in a manner similar to direct manual operation. The distant control panel may have the route levers or keys situated at the route entrance points on a panel diagram ; operation of a route lever or key transmits a code signal of the constant total code type and unless this signal is correctly received, and thereby allows a return indication to be sent to the distant control panel, the apparatus will not complete its operation. The routesetting equipment may be of the form described in Specification 496,495 employing sequence switches. Return indications of the condition of track occupation, signals, and points at all the way stations may be provided, for instance by a continuously operating system of the form described in Specification 461,136, [Group XXXVIII]. Individual code operation of the points is also provided. Figs. 2, 2A show the code transmission arrangement at the distant control point and Fig. 3 shows the receiving apparatus at the way station. On operating a route key at the distant control point, a rotary search switch moves to a determined setting and thereupon causes a rotary transmission switch to operate whereby a code consisting of three groups of break impulses is placed on the line wire ; at the way station the groups of impulses energize relays in hundred, ten, and unit groups and on the completion of the code, a relay corresponding to the route key is energized. The contacts operated by the cams B, C, D of the rotary switches are closed in the range of positions denoted by the adjacent linked numerals, but the contacts operated by the cam A are open in the positions denoted by the adjacent numerals. When the operator at the distant point operates a route key 21RK, a relay SS is energized from +ve, over back contact 21lr1, resistance 21YA, winding of the relay SS to - ve. A front contact 8s1 thereupon closes to energize the' clutch magnet SM for the search switch and the motor relay MS for the common drive of all the switches. This circuit is from +ve, over back contact st3, front contact ss1, cam contact TC 18¢/1¢, to the windings of clutch SM and relay MS. The search switch therefore rotates until it reaches position 1, whereupon cam contact SB 18¥/1 extends the potential from key 21RK and back contact 21lr1 to relay ST which thereafter sticks by its contact st1 and cam contact TD 1/18. Contact st3 breaks its back contact to deenergize the clutch magnet SM and makes its front contact to energize the clutch magnet TM for the transmission switch over cam contact TB1; the clutch TM continues energized over cam contact TA 1.15¢ so that the transmission switch moves to position 15¢. During this movement the cam TQ periodically opens the circuit from front contact @8/2 to a relay IS which by opening its contact is1 puts break impulses on the line wire L1, L2 but such impulses are made to lie in spaced groups, constituting a code corresponding to the particular route key operated, by reason of the relay IS being at times energized for a longer period. For instance with the route key 21RK operated and the search switch being stopped in position 1 it will be seen that potential is placed on the lead b over cam contact SP1/2 and on lead k over cam contact SP1 and back contact 21lr3; this results in the relay IS being energized while the transmission switch is passing from positions 3¥ to 5¥ and from positions 8“ to 10“ and therefore the break pulses given by the cam TQ are separated into three groups with two four, and seven break pulses respectively and so give a code 247. The relay IS is maintained energized by cam TP from position 14“ to 18 whatever the code but the movement is not completed until a return indication is automatically given that the code has been correctly received ; in preparation for this a relay FPR is energized over cam contact TD 15¢/18¢ and thus its contacts fpr1, fpr2 connect the line wire L1, L2 to a relay RC so that when the return indication is received a contact rc3 closes a circuit over cam contact TB 15¢ and the transmission switch then completes its movement. All the codes are chosen so that their three digits add up to thirteen. If the return indication is not received a fault indication lamp FIL remains lit over contact fpr3. The operator so notified may then effect the homing of the transmission switch by briefly operating a push FK which energizes a slow relay CFG; a contact cfgl then picks up a relay CF which closes its contact cf2 to effect the homing in the same manner as by contact rc3. The code transmitted to the way station operates the relay IR, Fig. 3. The first make period operates a slow relay RG which with its repeater relay RGA remains up throughout the code. A contact rga1 then operates a slow relay DC over a back contact ca1. The relay DC has a repeater relay DCA and accordingly a front contact dca2 energizes a relay DMA over a back contact hdxl ; the relay DMA has a stick contact dma2. At the end of the make pulse a circuit is closed from +ve, over back contact ir1, front contact dca1, back contacts poa1, pe2 to a relay PO; when the back contact ir1 opens (on the next pulse) the relay- PO is held by a circuit from +ve over front contacts rga1, dma4, winding of a relay POA, front contact po1, back contact pe2 and winding of relay PO; a front contact po2 extends the potential to a relay CA which registers the first break pulse. The contact ca1 changes over but the relay DC remains energized during the transmission of a group of break pulses by the intermittent energization over back contact ir1 to front contact dca1. The second break pulse is registered by the relay PE being energized over back contact ir1 and front contacts dca1, poa1 and in turn causing the relays PO, POA to be de-energized (by opening back contact pe2) whereby front contact po2 opens and permits the potential applied over front contacts rga1, dma4 to energize the relay CB (in series with CA over front contact ca2). Succeeding break pulses in the group are registered in a similar manner by the alternate operation of the relays PO, PE. At the end of the group a pause occurs so that the relay DC and its repeater relay DCA drop whereupon the code digit registered on the relays CA ...... CG is transferred to the hundredregistering relay bank HDA ..... HDG. With a code 247 the hundreds digit 2 registered by the relay CB is transferred to the hundred registering relay HDB by this latter relay being energized from +ve over front contact rga1, back contacts dca2, dme3, cg3, cf2, ce3, cd2, cc3, and front contacts cb2, dmb2. The relay HDB is held by a lower stick winding energized over contact hdb1 from the front contact rga1 through a relay HDX. The energization of the relay HDX causes the contact hdx1 to change to its front point resulting in the dropping of relay DMA and the energization of relay DMC whereby tne tens digit is later registered on the relay back TNA ..... TNG. The relays CA ..... CG are dropped by the opening of contact dma4 in readiness to register the next digit (the tens digit 4 of the code 247). For instance the tens digit 4 causes relays CA ... CD to be energized over contact dmc4 (in conjunction with the relays PO, POA, PE) and at the following pause this digit is registered by relay TND being energized from +ve over front contact rgal, back contacts dca2, dme3, cg3, cf2, ce3, front contacts cd2, dmc8. The relay has a lower stick winding energized in series with a relay TNX. The relay TNX changes over its contact tnxl whereby a relay DME is energized so that the units digit of the code is later registered through contact dme4 on the relays CA ... CG. The unit 7 of the code 247 energizes the relay CG and on the completion of the code a route setting relay 21DLR is energized by current from +ve over front contact rgal, back contact dca2, through the winding of a relay OK, front contacts cg3, dme5, hdb2, tnd2, to the winding of the relay 21DLR. The route setting relay 21DLR remains energized over its contact 21dlr1 and a second winding. The energization of the relay OK closes contacts ok1, ok2 to give the return indication that the code has been correctly received. Considering again -the apparatus at the distant control point it will be seen that the closure of the contact rc2 (on receipt of the return indication) energizes a high resistance winding of a relay AR by a circuit from +ve over front contact rc2, cam contact TE 15¢, cam contact SKI, winding of a relay 21LR, resistance 21YB to -- ve. The relay AR has a second winding energized over front contact ar1; the closure of a front contact ar2 shunts out the high resistance winding 'and the relay 21LR is then effectively energized and thereafter continues energized over its own front contact 21lr2. The route-setting relay 21DLR at the way station can only be dropped by returning the distant control key 21RK to its upper position. Such action results in a code 256 being transmitted since front contact 21lr3 now applies potential to lead l instead of lead k. At the way station this results in the potential from the front contact rgal being applied to a lead 256, connected to the negative side of the relay 21DLR which then drops since it no longer has a voltage. At the distant control point the relay 21LR is dropped in a similar manner-by the return indication causing potential from front conta