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Post by d7666 on Jun 18, 2019 11:39:08 GMT
Wasn't sure to put this under signalling or under Met. line !
Chilterns main line DMU classes 16x have tripcocks for the Harrow - Amersham section.
My question is, when two or more 16x are coupled and work in multiple, do all tripcocks on the train remain active or is there some kind of on-board cut-out mechanism that leaves only the forward-most front tripcock and rear-most rear tripcock active ? Visual checking such a formation shows all the tripcock remain down, but that can't determine if they are all active.
--
Nick
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Post by Dstock7080 on Jun 18, 2019 12:04:43 GMT
Wasn't sure to put this under signalling or under Met. line ! Chilterns main line DMU classes 16x have tripcocks for the Harrow - Amersham section. My question is, when two or more 16x are coupled and work in multiple, do all tripcocks on the train remain active or is there some kind of on-board cut-out mechanism that leaves only the forward-most front tripcock and rear-most rear tripcock active ? Visual checking such a formation shows all the tripcock remain down, but that can't determine if they are all active. -- Nick They wouldn't remain active as when the middle cab went passed a red signal, activated by the first set of wheels going over the blockjoint, the associated trainstop would be up, thus tripping the train. |
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Post by d7666 on Jun 18, 2019 13:28:01 GMT
Wasn't sure to put this under signalling or under Met. line ! Chilterns main line DMU classes 16x have tripcocks for the Harrow - Amersham section. My question is, when two or more 16x are coupled and work in multiple, do all tripcocks on the train remain active or is there some kind of on-board cut-out mechanism that leaves only the forward-most front tripcock and rear-most rear tripcock active ? Visual checking such a formation shows all the tripcock remain down, but that can't determine if they are all active. -- Nick They wouldn't remain active as when the middle cab went passed a red signal, activated by the first set of wheels going over the blockjoint, the associated trainstop would be up, thus tripping the train. Indeed, but this is exactly where my question gets complex. How is this done ? What about rear tripping ? Do Chiltern drivers manually isolate intermediate tripcocks on attaching ? And in turn re-instate on detaching ? Take two units coupled. Is the multiple unit system clever enough that when mating two it leaves just the leading tripcock of the lead unit and the trailing tripcock of the rear unit active, and de-activate the other two ? Then three units (and Chiltern do run 2+2+2 and 2+2+3), where the middle four tripcocks are inactive, which means the middle unit has no active tripcocks. Looking at a cabling diagram of 16x type unit couplers I can't see where this is implemented. And, if it is only the lead unit that has active tripcocks, does rear tripping only trip for example a 4car of 2x2 car after two cars have passed over, and the rear car of the lead unit trips ? -- Nick |
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Post by norbitonflyer on Jun 18, 2019 15:00:50 GMT
This is not peculiar to Chiltern - How did/does it work on Underground trains with cabs in the middle? Some of which would, in the past, have coupled and uncoupled during the working day (e.g R stock as built)
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Deleted
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Post by Deleted on Jun 18, 2019 15:47:21 GMT
Rear tripping would only occur if a fault developed with the associated Trainstop. Remember all trip cocks are on the right of the cab in it’s facing direction.
Trip cocks in the middle of trains are usually just cut out by train maintainers when trains are formed in the depot
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Post by Dstock7080 on Jun 18, 2019 16:18:10 GMT
This is not peculiar to Chiltern - How did/does it work on Underground trains with cabs in the middle? Some of which would, in the past, have coupled and uncoupled during the working day (e.g R stock as built) LT/LU automatic couplers dealt with this “automatically” ! (hence the name) Middle tripcocks were isolated upon coupling and automatically reset upon uncoupling. The middle tripcock isolating cock (yellow) changed its use on coupled cabs, to become Train Line Isolating Cocks. R Stock had automatic couplers at the normal coupling points, although Ward couplers on the West end only. Later 1973 / D / 1983 etc had electric pressure switch tripcocks so are not connected to the train line air pipe. D Stock could not be rear tripped (only an indication was shown in the leading cab) , as these were electrically Isolated, however the S Stock CAN be rear tripped while in service! Progress!! |
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Post by norbitonflyer on Jun 18, 2019 20:20:27 GMT
How does rear-tripping happen? I understood the tripcock is on the right hand side of the cab, so the one at the rear is on the wring side to be tripped by the lineside apparatus. (Forgive my ignorance, if the trainborne equipment is the actual tripcock, what is the lineside apparatus called? (or vice versa))
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Post by Dmitri on Jun 18, 2019 20:27:52 GMT
what is the lineside apparatus called Trainstop. |
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Post by 100andthirty on Jun 19, 2019 19:37:22 GMT
D Stock 7080......I really hope there are no active trainstops in the centre roads at White City, Golders Green and Morden!!!!!!
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Deleted
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Post by Deleted on Jun 19, 2019 19:43:00 GMT
Pre resignalling there was
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Post by Dstock7080 on Jun 19, 2019 21:01:26 GMT
D Stock 7080......I really hope there are no active trainstops in the centre roads at White City, Golders Green and Morden!!!!!! Apologies quite right, thinking old school again ! I’ll delete the post when I’m able on home pc. |
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Post by d7666 on Jun 20, 2019 11:59:00 GMT
How does rear-tripping happen? I understood the tripcock is on the right hand side of the cab, so the one at the rear is on the wring side to be tripped by the lineside apparatus. (Forgive my ignorance, if the trainborne equipment is the actual tripcock, what is the lineside apparatus called? (or vice versa)) Potentially anywhere where both direction moves can take place including into a terminal platform . You are right in location of tripcocks and trainstops under offside of train in direction of travel, but: I'll probably over simplify this, and not use the correct terminology, but consider travelling eastbound on reversible track for example, to proceed not only do your e/b trainstops have to be lowered, the w/b trainstops under your line of route also have to be lowered else will trip the tripcocks under the rear cab left had side in your current direction of travel. If it is a for a reversing move, when you go back w/b then the e/b trainstops also have to be lowered. Rear tripping is when one of the rear tripcocks does make contact with one of the "wrong direction" trainstops. |
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Post by philthetube on Jun 21, 2019 0:49:48 GMT
You don't have to have a train stop to be rear, or front tripped, it can happen with any obstruction trackside, very common are footballs and it open sections dead badgers.
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Post by Dmitri on Jun 21, 2019 6:20:50 GMT
it can happen with any obstruction trackside, very common are footballs and it open sections dead badgers. Or, sometimes, dead pigeons. |
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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 21, 2019 23:15:43 GMT
Presumably the middle trip cocks isolate automatically when the couple button is operated in the cab being coupled. The modern NR stock uses the Westcode brake or a variant of it so the trip would be an electoric switch. In the old days of proper rollig stock, the trip cock would have to be cut in or islated by the driver or secondman operating a valve on the loco or leading end and manually resetting thr trip cock. I used to have to do that when I was a secondman at Kings Cross.
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Post by d7666 on Jun 23, 2019 13:51:15 GMT
Presumably the middle trip cocks isolate automatically when the couple button is operated in the cab being coupled. The modern NR stock uses the Westcode brake or a variant of it so the trip would be an electoric switch. In the old days of proper rollig stock, the trip cock would have to be cut in or islated by the driver or secondman operating a valve on the loco or leading end and manually resetting thr trip cock. I used to have to do that when I was a secondman at Kings Cross. Indeed, I don't disagree with this as a presumed method of operation as to how it might work, but it still does not answer the overriding question that is: is it even implemented. -- Nick |
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