AHB Auto Half Barrier Circuit Based on MKII installation

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1 AHB Auto Half Barrier Circuit Based on MKII installation This document is not endorsed by Network Rail. It is NOT for installation, commissioning, testing or maintenance purposes, it is for information only. Network Rail s own documents must be followed at all times, however; this contains re-written extracts from railway standards. Copyright F. M. Spowart Version One May 2015

2 AHB Auto Half Barrier Circuit Page Two of Six Treadles (strike-in) to ensure TC occupies IBJ s A B Track circuit Treadle (exit A/B ) Use the basic track layout above with the following flowchart: THESE STYLE BOXES DESCRIBE THE FUNCTION OF THE RELAY THESE STYLE BOXES DESCRIBE THE SEQUENCE OF OPERATION THESE STYLE BOXES DESCRIBE WHAT IS HAPPENING AT LC & SB REPEAT RELAY OF TPR & TR (TRACK CIRCUIT OCCUPIED/CLEAR) STRIKE IN TC STICK RELAY. DROP WITH STRIKE IN TC. WILL NOT REPICK UNTIL EXIT CONDITIONS MET/TIME RELEASE ACTIVATED/OR BARRIERS RAISED USING LCU 10 SECOND TIMER RELAYS. THESE DROP WHEN STRIKE-IN TC OPERATED AND THEN START TO TIME. THIS IS TO ENSURE BARRIERS ACTIVATE AT THE CORRECT DISTANCE TRAIN OCCUPIES TRACK CIRCUIT A A T1PR DROPS A TPSR DROPS A SR PICKS AFTER 10 SECONDS, 1 & 2 TJR S DROP SIGNALLER RECEIVES WORKING INDICATION FOLLOWS JCSR, IF TJR s DON T PICK WITHIN 3 SECS OF EACH OTHER, THIS RELAY WILL PICK TJPSR DROPS COMPARES TIME OF TJR s AND IF 3 SECS DIFFERENCE IT WILL RE- PICK THEM DROPS (CON)JPR AFTER 7.5 SECONDS AFTER AMBER LIGHTS HAVE LIT CUTS FEED OFF TO BARRIER VALVES (CON)JR DROPS AFTER 7.5 SECS (CON)JPR DROPS (CON)SR DROPS AFTER 3 SECONDS HJR DROPS HJPR DROPS RED ROAD LIGHTS SHOW JCSR PICKS AMBER LIGHTS SHOW YODALS SOUND TIMER RELAY ENSURES AMBER ROAD LIGHTS SHOW FOR 3 SECONDS DROPPING ACTIVATES RED ROAD LIGHTS. IT CAN ONLY RE-PICK IF BARRIERS ABOVE 42 DEGREES AND RE-DROPS IF EJR DROPS SEE NEXT PAGE (A) SEE NEXT PAGE (B)

3 AHB Auto Half Barrier Circuit Page Three of Six FROM PREVIOUS PAGE (A) FROM PREVIOUS PAGE (B) BARRIERS FALL BELOW 81 DEGREES RECR PICKS PROVES THE AMOUNT OF ROAD LIGHTS LIT. (UP)KR DROPS SWITCHES ON BOOM LIGHTS BOOM LIGHTS ILLUMINATE IF SUFFICIENT LAMPS ARE LIT IF INSUFFICIENT LAMPS LIT ONE LEFT HAND LAMP OUT ON A POST TOGETHER WITH A RIGHT LAMP OUT ON ANOTHER POST WILL CAUSE THIS RELAY TO REMAIN DE-ENERGISED TO INDICATE LAMPS FAILED TO TECHNICIAN RECPR PICKS BARRIERS FALL BELOW 4 DEGREES RECPR REMAINS DE-ENERGISED SEQUENCE WILL CONTINUE, BUT BARRIERS WILL NOT RAISE AFTER TRAIN HAS PASSED EJR PICKS (SEE LATER) (DN)KR PICKS PROVES BOTH BARRIERS HAVE COMPLETED DESCENT, AND PROVIDES ONE FEED TO EJR TRAIN STRIKES EXIT TREADLE THEN DROPS APPROX 7 SECONDS AFTER LAST PRESS OF ARM A/B QRR PICKS A/B QRSR PICKS & STICKS REGISTERS TREADLE ARM PRESSED REPEAT STICK RELAY OF QRR TRAIN OCCUPIES TRACK CIRCUIT B REPEAT RELAY OF TPR & TR (TRACK CIRCUIT OCCUPIED/CLEAR) B T1PR DROPS B TPSR DROPS EXIT TC STICK RELAY. DROPS WITH EXIT TC. WILL NOT REPICK UNTIL FULL EXIT CONDITIONS MET/TIME RELEASE ACTIVATED/OR BARRIERS RAISED USING LCU TRAIN CLEARS TRACK CIRCUIT A A T1PR PICKS (SEE T1PR ABOVE) SEE NEXT PAGE

4 AHB Auto Half Barrier Circuit Page Four of Six FROM PREVIOUS PAGE A TPSR PICKS A/B QRSR DROPS YODALS TURNED OFF (CON) SR PICKS* HJR PICKS *ONLY IF RECPR PICKED EARLIER JCSR DROPS (CON)JR PICKS (CON)JPR PICKS EJR DROPS & STARTS TIMING TIMER THAT RE-STARTS SEQUENCE IF BARRIERS DO NOT RAISE WITHIN 7.5 SECONDS FROM (CON)JPR DROPPING STICKS (CON)JR BARRIERS RISE ABOVE 4 DEGREES (DN)KR DROPS VALVES & MOTORS ENERGISED IF (UP)KR FAILS TO PICK IN 7.5 SECONDS, EJR WILL DROP HJPR AND RE-ILLUMINATE RED ROAD LIGHTS BARRIERS RISE ABOVE 15 DEGREES HJPR PICKS RED LIGHTS EXTINGUISH RECR DROPS BARRIERS RISE ABOVE 81 DEGREES BARRIERS RISE ABOVE 83 DEGREES RECPR HELD BY HJPR MOTOR FEED CUT OFF & VALVES CLOSED HOLD BARRIERS UP TRAIN CLEARS TRACK CIRCUIT B SEE NEXT PAGE

5 AHB Auto Half Barrier Circuit Page Five of Six FROM PREVIOUS PAGE IF EXIT TRACK FAILS TO CLEAR THEN A/B JR WILL START TIMING, WILL THEN PICK A/B JPR AND AFTER 120 WILL RESTART SEQUENCE UNTIL THE TRACK CLEARS B T1PR PICKS B TPSR PICKS A SR DROPS SIGNALLER RECEIVES RAISED INDICATION NOTE: IF STRIKE-IN TRACK CIRCUIT FAILS WITHOUT PRESENCE OF A TRAIN, THE SEQUENCE WILL BE INITIATED AND BARRIERS WILL REMAIN DOWN. WHEN THE TRACK CLEARS, THE A/B JR WILL START TO TIME OUT AND PICK A/B JPR, RAISE BARRIERS AND RESTORE BARRIERS RAISED INDICATION. THIS WILL HAPPEN IF TRACKS WERE TESTED ON MAINTENANCE UNLESS THE LC WAS TAKEN ON LOCAL CONTROL, THEN LCU UP CIRCUIT WILL MAINTAIN (CON)SR STICK PATH. Indication to the signalbox is sent via either three or four wire operation. Three wire uses a common negative, and the other two wires used for raised and power off indication. No voltage gives working indication. With four wire operation both the negatives are maintained all the time. Only the positive uses one of the two other wires for raised power on and the other wire for raised power off, no voltage gives working indication to the signaller. Relay normal positions when crossing normal (barriers raised): Relay UP Relay DOWN A T1PR A SR A TPSR B SR B T1PR A/B QRR B TPSR A/B QRSR (LCU)DOOR CR A/B JR (Y/Z)CR (BARRIER DOORS) A/B JPR (LCU) (N) CSR (NOT ON LOCAL CONTROL) (DN)KR (PO)PR (POWER ON) JCSR (UP)KR EJR 1 TJR RECR 2 TJR (CON)SR HJR HJPR

6 AHB Auto Half Barrier Circuit Page Six of Six Relay UP (CON)JR (CON)JPR RECPR TJPSR Relay DOWN Relays not mentioned in flowchart above: (CON)YR ZCSR TZSR TZJR (UP) QRCSR or (DN)QRCSR (NS)R (NS)SR (DWL)R (DWL)ECR Combines the directional controls for all four approaches on double-line bi-directional AHB s. Prevents sequence of road lights if LCU lower/hand switch is turned with barriers up and either pedestal door open or Y/Z(DOOR)CR has failed. Track special relay used for a berth track for a regulated signal. Once dropped it requires overrun track circuit occupied or a treadle activated. It is used to prevent a train disappearing due to rusty rails. Timer used for above relay. Used in conjunction with QRSR, it proves the treadle for direction it states has been normalised after passage of a train Non-stopping train repeat of button in SB Stick relay for above Drivers white relay Drivers white light proving relay Differences between Mark I and Mark II installations: Mark One Penguin style pedestal mounted on a concrete pillar, with metal framework, hydraulic power pack with hoses. Removable top and bottom very flimsy plastic covers (called guillotine covers). LCU inside one of the pedestals, with push buttons and lever over auto button. Road lights and bells (later Yodals) fixed to same concrete post as the pedestals. Barrier booms made from wood. Barrier weights inside pedestals. Earlier installations had neon Another Train Coming signs (later abolished). Telephones to signalbox inside flap on pedestals. Relay (CON)R used. ECR s used in light circuits. Mark Two One piece steel 843 type pedestal with two hinged access doors and microswitch on handle side. Contains sealed hydraulic power pack. But better weather protection compared with a Mark One. LCU in post near one of the pedestals containing three-position switch. All four road lights have their own post. Two yodals fixed to two posts. Barrier booms made from tubular metal. Barrier weights on end of barriers. Another Train Coming signs are metal retro reflective type. Telephones on their own posts. Relay changed to a stick relay [(CON)SR] RECR relays used. The circuitry between both varies with some relays abolished/added. >>>END<<<

Morwell. (88 miles 75 chains 47 links, km)

Morwell. (88 miles 75 chains 47 links, km) Morwell (88 miles 75 chains 47 links, 144.372 km) 01.06.1877 Opened with line between Morwell and Sale. Staff and Ticket not provided initially. (VR to 62, Leo Harrigan, WTT) (01.04.1878) By this date,