route relay interlocking

Route Relay Interlocking

Circuitry to set a route

Setting a route from Signal 5 to Signal 9

Normal state of relays is that PBCR, DJR, DCR are energised and the remainder de-energised.

1. Entrance button for Signal 5 is pressed.

Note: For an eNtrance-eXit (Nx) panel there is a push button at the entrance of each route, and the route is cleared by first depressing the entrance button and then the exit button. To restore replace the signal or free initialise the cancellation of the route, the entrance button is pulled out. The buttons have three positions and are spring returned to the central position after being depressed or pulled. The buttons need are not be both held depressed simultaneously to clear set the route but the operation must follow the entrance-exit sequence.

1. Entrance button for Signal 5 is pressed

2. Relay 5(F)R energises and 5(FM)R already energised

Note: F = made when button pushed (=from)

FM= made when button is pushed or in mid position; i.e. it is pull to break

1. Relay 5(F)R energises (picks up) 2. PBPR picks up

1. Relay 5(F)R energises (picks up) 2. PBPR picks up3. Start relay 5(S)R picks up (for 1(S)R read 5(S)R) which

holds via DJR up and 5(FM)R up

5(S)R stick path

1. 5(S)R picks up (S)PR (for 1(S)R read 5(S)R)

1. 5(S)R picks up (S)PR (for 1(S)R read 5(S)R)2. On the panel the entrance button begins to flash as PBK(F)R picks

up Note:that 5(S)R is located at the remote relay room which picks the

repeat relay 5PBK(F)R at the panel which will then light 5PBKE.

1. The entrance button is released 5(F)R de-energises (drops) 2. PBPR drops and PBCR picks

1. After PBCR picks up, TFR picks up via (S)PRNote: Thus making all buttons be regarded as possible exits rather than the start of a different route

TFR Stick path

1. The exit button is now pressed Relay 9(F)R energises (picks up) 2. PBPR again picks up

Note: Once the (F)R drops the (S)R will be up until such time as a valid button is pressed as an exit and either the route sets, or timeout occurs or the entrance button is pulled.Once a (S)R= start relay is up, the TFR = transfer picks up thus making all buttons be regarded as possible exits rather than the start of a different route. Once a button is pressed there is an opportunity to set a route (for a time fixed by the DJR) after that the circuit resets to its quiescent state and with the TFR down all buttons are regarded as entrances again. Also note that on these circuits the 9(S) never times out until a (D) has been selected and route given a chance to set; on some designs there is a separate (longer) timeout of a flashing entrance button if no destination selected (signaller decision time, rather than equipment operation time).

1. 9(D)R picks up which holds via DJR up (for 5(D)R read 9(D)R)

9(D)R stick path

1. 9(D)R picks up which holds via DJR up (for 5(D)R read 9(D)R)2. (D)PR picks up as a result of 9(D)R energising

9(D)R stick path

1. 9(D)R picks up which holds via DJR up (for 5(D)R read 9(D)R)2. (D)PR picks up as a result of 9(D)R energising

9(D)R stick path

1. 9(D)R completes the circuit for the release of 5ANLR which picks up 5ARLR which holds to the route controls

2. The route availability (opposing routes normal, opposing route locking for directly and indirectly opposing routes, points “correct of free to go” etc.) conditions are constantly being monitored by the B50 voltage applied to 5A NLR coil.

3. 9(D)R picking completes the N50 side of the circuit for the release of 5A NLR and once this has been proved to have responded also the which picks up of 5A RLR.

4. 5A RLR then sticks up provided that the route availability conditions remain satisfied and the entrance button is not pulled and TORR conditions are not fulfilled.

1. 9(D)R completes the circuit for the release of 5ANLR which picks up 5ARLR which holds to the route controls

2. The route availability (opposing routes normal, opposing route locking for directly and indirectly opposing routes, points “correct of free to go” etc.) conditions are constantly being monitored by the B50 voltage applied to 5A NLR coil.

3. 9(D)R picking completes the N50 side of the circuit for the release of 5A NLR and once this has been proved to have responded also the which picks up of 5A RLR.

4. 5A RLR then sticks up provided that the route availability conditions remain satisfied and the entrance button is not pulled and TORR conditions are not fulfilled.

1. (D)PR picks up as a result of 9(D)R energising2. DCR drops as a result of (D)PR de-energising

1. (D)PR picks up as a result of 9(D)R energising2. DCR drops as a result of (D)PR de-energising3. DCR de-energises DJR which holds for 1 second Note: Often the DJR is set to several seconds;

there is also a “DJR hold” facility so that the technician can override the timeout feature to enable fault finding should a route be unable to be set.

1. DJR releases which releases 5 (S)R and 9(D)R2. 5 (S)R and 9(D)R respectively release (S)PR and (D)PR

1. 5 (S)R and 9(D)R respectively release (S)PR and (D)PR

1. 5 (S)R and 9(D)R respectively release (S)PR and (D)PR2. Relay DCR now picks up via (D)PR down

DCR stick path

1. Relay DCR now picks up via (D)PR down and DJR also picks up

1. Relay DCR now picks up via (D)PR down and DJR also picks up2. Relay (S)PR down also releases TFR

1. On the panel the release of 5(S)R cancels the flashing light shown in the entrance button

2. PBKR picks up which in turn allows a steady 24 v supply to PBKE and thus the button light is permanently illuminated

1. The exit button is may be released as soon as its push has been registered; it can be released before the entrance button is becomes steady.

2. PBPR releases and PBCR picks up

Route Relay Interlocking

Point Control

1. Point Control – due to the high power consumption of point machines and clamp locks, it is usually impractical to feed them direct from an interlocking. Instead they are usually controlled indirectly form a location adjacent to the points.

2. Control Circuits – The NWR and RWR relays repeat the position of the point lock relays in the interlocking using a 2 wire ‘polar' circuit.

3. The current drawn varies from 5 to 15 amps with the higher initial surge as the points start to move and so a BR943 contactor relay is required for switching these currents

4. The NKR and RKR are provided at the location adjacent to the point ends. These relays feed the NWKR and RWKR detection circuits back to the interlocking, this circuit additionally proves the contactors de-energised

1. The point lock relays, NLR and RLR are separate relays. They are electrically interlocked and magnetically latched after each operation. Each relay has two coils; one to be operated and fulfil the circuit requirements and the other to release the magnetic latch via its energised contact which is internally wired. In the route lock relays e.g. 5A the NLR only is latched and the RLR only has a single coil

2. Assume 102 points stand reversed and are required normal (as for route 5A). The route calling relay 5A RLR picks up which unlatches 102 RLR and operates 102 NLR. This in turn operates 102 NWR which drives the points to the normal position. On completion of the point movement 102 NWKR picks up to prove that the points are now correctly normal

1. The point lock relays, NLR and RLR are separate relays. They are electrically interlocked and magnetically latched after each operation. Each relay has two coils; one to be operated and fulfil the circuit requirements and the other to release the magnetic latch via its energised contact which is internally wired. In the route lock relays e.g. 5A the NLR only is latched and the RLR only has a single coil

2. Assume 102 points stand reversed and are required normal (as for route 5A). The route calling relay 5A RLR picks up which unlatches 102 RLR and operates 102 NLR. This in turn operates 102 NWR which drives the points to the normal position. On completion of the point movement 102 NWKR picks up to prove that the points are now correctly normal

WZR is slow to release

1. When it is desired to move the points as a result of setting a route by the entrance and exit button (or by the use of the individual point key) the appropriate NLR or RLR relay is energised. Assuming that the points are free and it is required to move them to the, for example normal position, both contactor relays NWR and RWR will be de-energised..

2. When relay NLR is energised NWR will pick up via WJR down. The energisation of NWR will move the points to the normal position. On the energisation of NLR, WJR will be energised but will not operate for 7-9 seconds. Normally during this time the point machine would complete its movement before WJR picked up, but in the event of an obstruction the motor would continue to run on the clutch which is undesirable. WJR is provided for the purpose of disconnecting the contactor relay and cutting off the supply to the machine.

WJR is slow to pick

WJR picks after 7.5 secs

1. In the meantime, on its release of 5A NLR has disconnected the cascade sectional release route locking and any others for opposing route locking. The route locking relays (USRs) are slow to operate (to provide a safeguard against ‘bobbing’ track circuits) but are also inherently slow to release, which gives 102 NLR time to operate before the USRs release

2. Note that 101 WZR maintains the USR until the point NLR or RLR has operated. This has the effect of causing the panel route lights to operate in sequence.

1. Finally in the point circuit 102 WZR releases and is used in other circuits to ensure that 102 points can no longer be set by any other route.

2. On the operation of 102 NWR and 102 NWKR, 102 NKLPR to prove that not only are points 102 normal but they are also locked and not being ‘called’ to the reverse position

1. At the panel the energisation of the NWKR will cause the signallers point key indication normal white light to illuminate

2. The dropping of the USRs and picking of the RLR will allow to NUKRs to pick which in turn light the relevant white route lights on the panel.

When the relevant track circuit indicating relay drops then the red light will illuminate on the panel and the white route light will extinguish

route relay interlocking

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