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Post by jamesb on Jul 24, 2017 4:07:24 GMT
Yesterday, I took a train from Roding Valley to Woodford. Every time the train accelerated, a single leaf door opened to 1cm. When I arrived at Woodford I reported this to the driver who said that he hadn't lost his pilot light.
When he closed the car doors (as the train terminated at Woodford and I was in car 2) the single leaf door shut tight, then clicked, and opened to about 1cm and could be pushed shut and open to 1cm without resistance.
How was this possible?
I guessed that the door seal may have shrunk, but it appeared intact. And the train had continued to accelerate without loss of pilot light.
I wondered if the spring in the 'push back' was loose but this wouldn't explain the 'click' and the failure of the pilot light to be lost.
I assume that the train was taken out of service.
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Post by aslefshrugged on Jul 24, 2017 6:11:03 GMT
On Sundays we drive in Coded Manual east of Leytonstone, if the door interlock had been lost then the motors would have cut out (along with the pilot light) and the train wouldn't have been able to accelerate. If the door interlock was maintained despite the door opening 1cm then the driver wouldn't have been aware of it.
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Post by plasmid on Jul 25, 2017 23:23:14 GMT
That's nothing. I saw someone standing freestyle who then inadvertently looked like a right proper numpty when he fell on to the single leaf door. Then as the 92ts train pulled in to Liverpool Street and started braking the door opened 1/3 of the way under the force of braking. He looked at the door and said "it shouldn't do that". I looked at him and said "you shouldn't have broken the door then". The train carried on as normal with the door opening and closing all the way to Bank before it stopped opening.
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Post by jamesb on Jul 26, 2017 10:04:25 GMT
Having researched the subject a bit (London Underground Electric Train, By: Piers Connor), I have read that historically: " The roller of one door in a leaf pair (or on each single door) was attached to the arm by a spring, which allowed the door to be pushed back 4in (10cm). This was provided to allow trapped limbs or clothing to be freed. The spring pressure had to be just right - stiff enough to keep the door closed against train acceleration and braking, but not so stiff it couldn't be pushed back a little".
I wonder if a similar arrangement operates on the 1992ts (although it has externally hung doors unlike earlier trains so the mechanism might be different).
Maybe the spring pressure wasn't high enough on my door?
The problem of passengers leaning on the doors causing the motors to cut out seems much greater on the 1992ts compared to other stock e.g. 1995/1996ts.
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Post by 100andthirty on Jul 29, 2017 7:27:32 GMT
jamesb. You are correct. This system applies to all LU's trains except S stock. As 2009ts Victoria line trains have obstacle detection sensitive edge, the spring pressure is higher so doors don't open with the combination of door/passenger inertia and acceleration/braking. It was retrofitted to the 2009ts as things were prone to be caught when people were inside the train but were sometimes hard to remove if the platform at the next staion was on thr other side.
You might ask why it hasn't been retrofittod to S stock? I stand to be corrected, but S stock doesn't seem to be prone to this problem....possibly due to the shape of the door relative to the floor.
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Post by firestorm on Jul 29, 2017 13:12:44 GMT
jamesb. You are correct. This system applies to all LU's trains except S stock. As 2009ts Victoria line trains have obstacle detection sensitive edge, the spring pressure is higher so doors don't open with the combination of door/passenger inertia and acceleration/braking. It was retrofitted to the 2009ts as things were prone to be caught when people were inside the train but were sometimes hard to remove if the platform at the next staion was on thr other side. You might ask why it hasn't been retrofittod to S stock? I stand to be corrected, but S stock doesn't seem to be prone to this problem....possibly due to the shape of the door relative to the floor. I believe that all LU trains, every double door had its own door engine therefore independent from each other, so fitting a spring back system on one door would be relatively easy. The doors on the S-Stock are operated by a single motor connected by a worm drive that drives both doors at the same time, so making one door sprung would either not be technically possible or difficult to implement. Also where the door engines are usually fitted underneath the seats, the S-stock ones are fitted overhead, so space might have been a reason for using this kind of door setup. Perhaps the obstacle detection and sensitive edge system is enough to reduce the need for a sprung door? Just my thoughts of course.
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Post by 100andthirty on Jul 29, 2017 15:51:42 GMT
firestorm.......The S stock design (and, originally 2009ts), the combination of obstacle detection and sensitive edge was indeed thought to make the sprung door not to be necessary. This has proved to be true for S stock and not for 2009ts.
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Post by norbitonflyer on Jul 30, 2017 7:37:19 GMT
I believe that all LU trains, every double door had its own door engine therefore independent from each other, so fitting a spring back system on one door would be relatively easy. I seem to recall that the door engines are mounted between the door openings, and work one leaf from each opening (rather than both doors of one opening). Thus why on the 1973 stock the single end door and one leaf of the adjacent pair could be left open at long stops.
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Post by 100andthirty on Jul 30, 2017 8:39:46 GMT
Norbitonflyer....what you said only applies to 1973ts
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Post by mcmaddog on Jul 30, 2017 10:24:35 GMT
Years ago I thought I read that the original door speed on the 92TS was too aggressive and the pressure was reduced a little to make them slower. Perhaps therefore there's slightly less pressure at all times and as a result their ability to stay closed under force is a bit less than designed.
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Post by superteacher on Jul 30, 2017 11:19:20 GMT
I also heard that the 73 stock doors closed too aggressively in their early days, and that this was modified.
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Post by flippyff on Aug 3, 2017 19:54:47 GMT
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Post by Chris W on Aug 3, 2017 20:10:12 GMT
Looking for a 12-14 year span? 92 stock into the 2030s..... ;-) HTIOI Simon Belt and braces for every eventuality IMO
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North End
Beneath Newington Causeway
Posts: 1,769
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Post by North End on Aug 3, 2017 20:22:37 GMT
Looking for a 12-14 year span? 92 stock into the 2030s..... ;-) HTIOI Simon Belt and braces for every eventuality IMO I wouldn't be at all surprised to see them reach the 2030s. If work is being done now, and a lot of money spent in the process, hopefully many of the biggest issues will be fixed to the extent that it keeps the trains going. It's always been the case that the trains were never going to be able to limp on until any replacement - the remedial work had to be done now. There are very many daily delays and cancellations attributable to these trains, and the money just isn't there now to replace them.
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Deleted
Deleted Member
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Post by Deleted on Nov 21, 2017 20:28:24 GMT
Hi all, First post. It is funny I read this, I remember a few years ago on a 1992 stock between Liverpool Street and Bethnal Green the single leaf end doors, one of them wasn't holding close properly and slide forward open (half way) whilst in motion in the tunnel. I was like WTF, especially as I was sitting near it. It had slide close upon braking slowing down entering Bethnal Green.
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Deleted
Deleted Member
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Post by Deleted on Nov 30, 2017 20:20:48 GMT
Having researched the subject a bit (London Underground Electric Train, By: Piers Connor), I have read that historically: " The roller of one door in a leaf pair (or on each single door) was attached to the arm by a spring, which allowed the door to be pushed back 4in (10cm). This was provided to allow trapped limbs or clothing to be freed. The spring pressure had to be just right - stiff enough to keep the door closed against train acceleration and braking, but not so stiff it couldn't be pushed back a little". I wonder if a similar arrangement operates on the 1992ts (although it has externally hung doors unlike earlier trains so the mechanism might be different). Maybe the spring pressure wasn't high enough on my door? The problem of passengers leaning on the doors causing the motors to cut out seems much greater on the 1992ts compared to other stock e.g. 1995/1996ts. Perhaps the Operating Experience gained with the 1992's External Sliding Doors was put to good use, and implemented on the 1995's and 1996'es external sliding doors, hence the performance enhancements the 1995's and 1996'es enjoy.
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Post by flippyff on Mar 17, 2018 21:12:06 GMT
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