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Post by Deleted on Apr 22, 2013 13:50:01 GMT
On departure from Clapham Common, the last set of double doors on this Northern Line train opened. The train continued moving for a while before the driver noticed and stopped in the tunnel.  What could cause this malfunction? The train op spent a long time trying to fix the problem, but the doors wouldn't budge. |
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Post by domh245 on Apr 22, 2013 15:51:34 GMT
Wow, That can't be good! Surely the Pilot light would have failed, and he wouldn't have been able to motor, or has the door just given in, but leaving the pilot lit? As for the incident, did you carry on eventually to the next stop and detrain, or did you do something else?
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Post by railtechnician on Apr 22, 2013 16:16:50 GMT
Interesting! I don't know but presume the end doors can be cut out on that stock as they can be on others. Again I don't know but perhaps that makes either faults and/or driver error more likely to cause end door open issues. I would've thought that even if the end doors are cut out they would remain in the pilot circuit but it would appear not.
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Post by Deleted on Apr 22, 2013 17:10:19 GMT
Wow, That can't be good! Surely the Pilot light would have failed, and he wouldn't have been able to motor, or has the door just given in, but leaving the pilot lit? As for the incident, did you carry on eventually to the next stop and detrain, or did you do something else? Passengers in car 6 were moved to car 5. Everyone was detrained at the next stop. As the train started moving from the platform, the doors opened (I was expecting this to automatically bring the train to a halt). After a while, the driver stopped and asked for the alarm to be pulled if any doors were open. The driver spent a while in the cab and under seats in the carriage, trying to fix the problem but the doors wouldn't close. Interestingly, after we all detrained, the button on the outside of the carriage that closes the doors didn't seem to have a problem with closing the faulty door. |
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Colin
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Post by Colin on Apr 22, 2013 17:19:14 GMT
The pilot dropping out only causes the motors to drop out - a loss of pilot light on its own won't demand a brake application..........so if a driver is coasting, they probably won't be aware straight away.
The end door cut out is for preventing a door from opening - it won't bypass the pilot light circuit!!
The driver did do the correct procedure in terms of stopping and asking for a handle to be pulled if there is a door open via the PA, but I'm rather concerned that there is no mention of a member of staff being posted in the affected carriage for the journey to the next station.
As for how it happened, well I wouldn't mind knowing the answer too!!
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rincew1nd
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Post by rincew1nd on Apr 22, 2013 18:25:44 GMT
It is appropriate to remind members of the rules when discussing this kind of thing:The question about what is a pilot light has been moved to its own thread here.
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Post by domh245 on Apr 22, 2013 18:28:23 GMT
ah, Ok, but the OP did mention that the train was leaving clapham common, so surely he would have been accelerating, unless he was going NB in which case there is a low PSR there which could explain why "The train continued moving for a while before the driver noticed and stopped in the tunnel". Why is it that I always end up answering my own Questions?  |
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Post by caravelle on Apr 22, 2013 18:49:01 GMT
The pilot dropping out only causes the motors to drop out - a loss of pilot light on its own won't demand a brake application..........so if a driver is coasting, they probably won't be aware straight away. The end door cut out is for preventing a door from opening - it won't bypass the pilot light circuit!! The driver did do the correct procedure in terms of stopping and asking for a handle to be pulled if there is a door open via the PA, but I'm rather concerned that there is no mention of a member of staff being posted in the affected carriage for the journey to the next station. As for how it happened, well I wouldn't mind knowing the answer too!! I find it strange that the doors don't have an acessible manual by-pass that would allow it to be closed and locked by hand and deactivated and a pilot light jumper that would allow that door to send a closed signal after electrical fault provided it can be closed and deactivated mechanically/by hand. As a safety precaution the jumper could only be inserted after the deactivating handle is moved, etc... Than take 2 enormous stickers and slap them on the door until the train can be seen to by a fitter or taken out of service. That should take no more than 5-10 min and reduce delays. |
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rincew1nd
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Post by rincew1nd on Apr 22, 2013 19:08:15 GMT
Other railway companies do have a similar system, doors out of use are locked and stickered as out of use. LU, however, simply takes the train out of service immediately; I presume because of a variety of problems caused when doors don't open infront of people (both inside and out).
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Chris M
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Post by Chris M on Apr 22, 2013 19:17:07 GMT
I find it strange that the doors don't [...] a pilot light jumper that would allow that door to send a closed signal after electrical fault provided it can be closed and deactivated mechanically/by hand. As a safety precaution the jumper could only be inserted after the deactivating handle is moved, etc... I'm not sure about that. Unless the jumper could only be physically placed when the doors were closed and they could not be opened with it in place, then I can see it being accidentally left in place and thus the safety provided by he interlock not being present for that door. As a separate question, how long does an override of the door interlock last? If, as in this case a door fails between stations then interlock will need to be overridden to move the train to the next station for detraining (after all the correct procedures have been done of course). If the door interlock then couldn't be obtained after detraining, would it have to be overridden again in order to move the train to the depot or would the previous override still be in effect until actively cancelled? |
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Post by rincew1nd on Apr 22, 2013 20:10:03 GMT
I find it strange that the doors don't [...] a pilot light jumper that would allow that door to send a closed signal after electrical fault provided it can be closed and deactivated mechanically/by hand. As a safety precaution the jumper could only be inserted after the deactivating handle is moved, etc... As a separate question, how long does an override of the door interlock last? In my mind it's a switch, possibly with a glass rod through it so you can tell if it has been activated. Having had a quick scooch around the web the only thing I can find that is similar to my mental image are these:  The switches covered with the brass flaps. |
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Post by Deleted on Apr 22, 2013 20:22:37 GMT
It's lucky it didn't happen when the train was full
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Post by caravelle on Apr 22, 2013 20:34:12 GMT
Quoting Chris MThat's why I've written: So, we've got 3 scenarios: Mechanical door actuation failure, electrical door failure (sensing or command) and both failures (improbable yet possible): Solutions: Mechanical door failure and electrical door failure (command): If it's a simple failure and the kinematics are ok then unclutch the door (or somehow disengage the system), close, lock and deactivate it. Pilot circuit should work. Electrical door failure (sensing) and and both failures: This affects the pilot circuit and the door should be closed as above (or automatically) and a jumper would be inserted. Again this jumper can only be inserted if the door is mechanically locked and it's power deactivated (whether electric or pneumatic) so you can only reactivate the door by physically taking the jumper out. Hope I've explained it better this time. |
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Post by Deleted on Apr 23, 2013 7:52:37 GMT
unless he was going NB in which case there is a low PSR there I can confirm that it was a NB train. It's lucky it didn't happen when the train was full Yes, thankfully this was not a serious incident as nobody was near the set of doors at the time. So, we've got 3 scenarios: Mechanical door actuation failure, electrical door failure (sensing or command) and both failures (improbable yet possible): The doors did close after detraining at the next stop, so this would suggest that it was an electrical failure rather than a mechanical? |
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Post by North End on Apr 23, 2013 9:19:32 GMT
On departure from Clapham Common, the last set of double doors on this Northern Line train opened. The train continued moving for a while before the driver noticed and stopped in the tunnel. What could cause this malfunction? The train op spent a long time trying to fix the problem, but the doors wouldn't budge. It is not appropriate to post in detail, however rest assured this incident has been the subject of an extremely thorough investigation. What I will say is that the train behaved in accordance with its design. Those with a more detailed knowledge of train equipment and design may be able to work out what happened, however I would request this is not further discussed on this forum in order to avoid reoccurrence. |
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Post by rincew1nd on Apr 23, 2013 10:15:16 GMT
In accordance with the request above and in accordance with the forum rules (as quoted above) this thread is now locked.
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