DWS
every second count's
Posts: 2,487
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Post by DWS on Feb 5, 2023 23:07:40 GMT
What are the locations of Tripcock Testers on the Bakerloo Line ?
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Post by Dstock7080 on Feb 6, 2023 7:04:56 GMT
Baker Street - both
Queens Park - approaching DOWN platform 4
Harrow & Wealdstone - UP platform
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Tom
Administrator
Signalfel?
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Post by Tom on Feb 6, 2023 9:38:13 GMT
Previously also at Kilburn Park both as a temporary measure in 2009. There was a plan in 2005/6 to install additional permanent testers at Kilburn Park and Charing Cross on both roads, probably eliminating the Baker Street ones as they're on a curve and were a reliability concern.
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Post by chepstow on Mar 20, 2023 23:07:01 GMT
I always assumed that a tripcock tester gave you some assurance that the tripcock was going to do its job. After an incident in the early 90s (I can't remember exactly when) we had an incident during a signal failure when trains had to trip past signals at danger, but on one train the Westinghouse didn't apply. It turned out the tripcock hose had been fitted twisted, so regardless of the trip arm the Train Line pressure was never lost. The driver's defence was that the previous Tripcock Tester had cleared - which was true - but the problem was that a Tripcock Tester is misnamed, it is only a trip arm detector. It does not prove the tripcock operation. You could weld a piece of angle iron onto a train to pass a TT. The only defence against such an error is for Fleet staff to actually do their tripcock test and bash the trip arm with a paddle on prep. But they didn't in this case. Or indeed on the 12 previous days on which they allegedly performed prep since the tripcock was changed. For context, I was in the Fleet organisation and we banged some heads.
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Post by Dstock7080 on Mar 21, 2023 7:14:19 GMT
I remember being a Guard on a relatively new westbound D Stock, the Driver called to say we’d need to “Apply the Rule” at two defective home signals at St. James’s Park. While staying on the cab-to-cab we went past the first signal and didn’t get tripped; the driver thought it must’ve cleared as the train went over.
Getting ready for the second signal we thought it very odd that the train wasn’t tripped again!
Detrained and ran empty, with me in the front cab.
Picked up the Area Manager at South Kensington.
Tripcock tester at Earl’s Court pfm.3 passed!
Trying to think how to test the tripcock, the Area Manager gave authority to enter Ravenscourt Park station at speed as the automatic starting signal had a timing relay for non-stopping trains (station was closed on Sunday).
All three of us were amazed when the red signal zoomed past without the train being tripped!
An incorrectly fitted air valve was the cause and required a fleet wide inspection. (D Stock had pressure-switch tripcocks).
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Post by blootop on Aug 29, 2023 15:21:55 GMT
I always assumed that a tripcock tester gave you some assurance that the tripcock was going to do its job. After an incident in the early 90s (I can't remember exactly when) we had an incident during a signal failure when trains had to trip past signals at danger, but on one train the Westinghouse didn't apply. It turned out the tripcock hose had been fitted twisted, so regardless of the trip arm the Train Line pressure was never lost. The driver's defence was that the previous Tripcock Tester had cleared - which was true - but the problem was that a Tripcock Tester is misnamed, it is only a trip arm detector. It does not prove the tripcock operation. You could weld a piece of angle iron onto a train to pass a TT. The only defence against such an error is for Fleet staff to actually do their tripcock test and bash the trip arm with a paddle on prep. But they didn't in this case. Or indeed on the 12 previous days on which they allegedly performed prep since the tripcock was changed. For context, I was in the Fleet organisation and we banged some heads. It’s not the only misnomer. The “brake test” doesn’t test the brakes at all. As long as the Trainline air pipe proves to be continuous, you could have no brake shoes fitted and you’d still pass the brake test. |
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towerman
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Post by towerman on Aug 29, 2023 17:04:19 GMT
I remember being a Guard on a relatively new westbound D Stock, the Driver called to say we’d need to “Apply the Rule” at two defective home signals at St. James’s Park. While staying on the cab-to-cab we went past the first signal and didn’t get tripped; the driver thought it must’ve cleared as the train went over. Getting ready for the second signal we thought it very odd that the train wasn’t tripped again! Detrained and ran empty, with me in the front cab. Picked up the Area Manager at South Kensington. Tripcock tester at Earl’s Court pfm.3 passed! Trying to think how to test the tripcock, the Area Manager gave authority to enter Ravenscourt Park station at speed as the automatic starting signal had a timing relay for non-stopping trains (station was closed on Sunday). All three of us were amazed when the red signal zoomed past without the train being tripped! An incorrectly fitted air valve was the cause and required a fleet wide inspection. (D Stock had pressure-switch tripcocks). Had the same thing happen on the Central back in the day,train failed to trip applying the rule,the chamber at the top of the tripcock had worked loose.Chap that signed it off as tested demoted to cleaner for two years. |
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Post by jimbo on Aug 29, 2023 20:37:30 GMT
It’s not the only misnomer. The “brake test” doesn’t test the brakes at all. As long as the Trainline air pipe proves to be continuous, you could have no brake shoes fitted and you’d still pass the brake test. I think that once happened to a train coming into service from Ealing Depot at Acton Town! A long time back! |
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towerman
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Post by towerman on Aug 29, 2023 21:30:58 GMT
In the early days of the Victoria Line guy was adjusting brake shoes,someone else was doing something on the train that applied the brakes and he kept winding them off,when the train entered service for the evening peak nothing happened when T/Op applied the brakes.
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
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Post by roythebus on Aug 29, 2023 22:17:50 GMT
"the Brake Test" is a misnomer, it's a brake line continuity test to check that any isolating cocks are in the open position. The "running brake test" is actually for testing the operation of the brake.
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Post by spsmiler on Aug 30, 2023 13:30:05 GMT
In the early days of the Victoria Line guy was adjusting brake shoes,someone else was doing something on the train that applied the brakes and he kept winding them off,when the train entered service for the evening peak nothing happened when T/Op applied the brakes. was this in the days when the back of a departing train and front of an arriving train were alongside the platform (in a way that was visible to all passengers) at the same time? |
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towerman
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Post by towerman on Aug 30, 2023 17:33:19 GMT
The home stick cleared when the rear of the train in the platform passed the starter.
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towerman
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Post by towerman on Aug 30, 2023 17:39:01 GMT
Back in the 70s was talking to the signal lineman at Seven Sisters,said when he was based at Wembley Pk one of the Met locos spadded a signal on the fast road,triparm went round in a full circle and reset itself.
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Post by philthetube on Sept 1, 2023 13:02:10 GMT
"the Brake Test" is a misnomer, it's a brake line continuity test to check that any isolating cocks are in the open position. The "running brake test" is actually for testing the operation of the brake. Running brake tests are no done on the underground when entering service. 95 stock, (when new), also had at least one incident of a train being tripped and the trip resetting itself. |
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towerman
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Post by towerman on Sept 1, 2023 16:48:07 GMT
Used to be the rule if more than 50% of brake blocks were changed on examination the train had to be shunted round the depot to ensure brakes were working.
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Post by t697 on Sept 2, 2023 16:22:44 GMT
Had the same thing happen on the Central back in the day,train failed to trip applying the rule,the chamber at the top of the tripcock had worked loose.Chap that signed it off as tested demoted to cleaner for two years. I don't know how often that failure mode happened but I recall doing the engineering investigation for what could well have been this same incident. Units had just been reformed with a middle cab becoming an end cab. Middle tripcocks are isolated from the Train Line (Brake Pipe) and should be latched up so they don't keep striking trainstops that rise as the front of the train drops the next track circuit. It appeared this hadn't been done or the latch was defective and the continued battering caused the bolts holding the valve to the top of the main body to stretch so the cam inside wouldn't open the valve. This led to a requirement to use better grade bolts. Suspicion was a well meaning bean counter had changed spec and supplier! However as already mentioned above, the reform test should have tested the tripcock and it seems that wasn't done, which would have revealed the fault and stopped the train entering service. Overall one less hazard on fleets without middle cabs. I suppose we must thank the signal failure for revealing the fault before the tripcock was called on to provide real protection...
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
Posts: 1,275
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Post by roythebus on Jun 24, 2024 23:23:38 GMT
When the Waterloo & city line was fitted with "Moorgate" train stops on the approach to Bank, I was the driver on the test train on a Sunday. A train stop was fitted just before the facing crossover into the "down" line platform. At 12 mph it worked; at 20 mph the train bounced sideways and din't get tripped. Fail!!
And in the days of single car operation, one mid-morning train left the Waterloo sidings and the brake never worked at all, nor did the handbrake. The fitters hadn't connected the linkage. the train rolled back and forth in the tunnel untntil coming to rest. After that incident single car working was abandoned.
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