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Post by Deleted on Dec 5, 2014 16:47:21 GMT
Hopped on a train the other day at my local Central Line station, onto the the third car which - hang on! i noticed was a driving cab. Number 91133 - what's it doing as the third carriage down in a set? Just wondered, if this is normal, or not - a maintenance thing, or if this set will be like this always! never seen that before on the Central Line.
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Post by Deleted on Dec 5, 2014 17:53:41 GMT
I've seen it as well it confused me a lot.
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North End
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Post by North End on Dec 5, 2014 19:04:11 GMT
Hopped on a train the other day at my local Central Line station, onto the the third car which - hang on! i noticed was a driving cab. Number 91133 - what's it doing as the third carriage down in a set? Just wondered, if this is normal, or not - a maintenance thing, or if this set will be like this always! never seen that before on the Central Line. Yes it is normal, the fleet was built with slightly more driving units than non-driving units to give flexibility. I can't remember the exact number off hand, but there will always be a small handful of trains with at least one cab in the middle. |
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Post by Deleted on Dec 5, 2014 21:55:45 GMT
I always thought that central line trains were 2x4 car units but I must be wrong.
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Chris M
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Post by Chris M on Dec 5, 2014 23:53:22 GMT
No, they are 4x2 car units. Just over half the units have a cab at one end ("A-B units" according to Squarewheels), the remainder only have shunting controls ("B-C units"). Normally a train is formed of A-B+B-C+B-C+B-A, but there are a handful of trains marshalled with three A-B units meaning there is a driving cab in the middle.
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metman
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Post by metman on Dec 6, 2014 9:39:17 GMT
Some of these middle motor cars have had equipment robbed from them such as drivers seats so will be confined to the middle portions of trains. This is not uncommon on fleets and the same happened with the 1967 stock although this was done on a more official bases. There is a historic thread about 1992 stock middle DMs floating about.
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Post by superteacher on Dec 6, 2014 10:26:03 GMT
Some of these middle motor cars have had equipment robbed from them such as drivers seats so will be confined to the middle portions of trains. This is not uncommon on fleets and the same happened with the 1967 stock although this was done on a more official bases. There is a historic thread about 1992 stock middle DMs floating about. I was under the impression that the 1992 stock DM's are all still operational. I have seen a DM in the middle of the train, but the next time I've seen the same DM it's been at the front. |
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Post by norbitonflyer on Dec 6, 2014 15:02:17 GMT
Normally a train is formed of A-B+B-C+B-C+B-A, but there are a handful of trains marshalled with three A-B units meaning there is a driving cab in the middle. Someone on Modern Railways worked out the number of permutations: Each of the two middle units can be marshalled either way round (BCBC*, BCCB or CBBC) Either or both C's can be replaced with an A to make another six, or a deicing unit (D) to make another six, or one of each to make another four (BABD, BDBA, BADB, ABBD) . That makes 19! * I am excluding mirror image permutations, so CBCB is the same as BCBC |
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North End
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Post by North End on Dec 6, 2014 18:00:12 GMT
Some of these middle motor cars have had equipment robbed from them such as drivers seats so will be confined to the middle portions of trains. This is not uncommon on fleets and the same happened with the 1967 stock although this was done on a more official bases. There is a historic thread about 1992 stock middle DMs floating about. I was under the impression that the 1992 stock DM's are all still operational. I have seen a DM in the middle of the train, but the next time I've seen the same DM it's been at the front. All the driving cars are officially operational, however from time to time it's not uncommon for a particular unit to be confined to the middle of a train if there's a defect or issue with equipment in a particular cab. Ideally it shouldn't happen, but if it's a choice between that or cancelling a train then the former is preferable, especially if it's a comparatively minor issue like for example a scratched windscreen or defective windscreen wiper, etc. In the more extreme cases this restriction can occur for longer, many on here will be familiar with the C stock unit 5555 which was confined to the middle for many years and in the end the issue never got repaired. It happens on the mainline as well, sometimes a particular cab may be confined to the middle of a train, for example due to defective AWS, this may mean it has to be confined to diagrams which do not split/join. |
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metman
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Post by metman on Dec 6, 2014 18:11:57 GMT
According to an old thread there are or were in 2011 3 cabs which are relegated to the middle of trains. I believe one was 91117.
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Post by astock5000 on Dec 6, 2014 21:02:43 GMT
Yes it is normal, the fleet was built with slightly more driving units than non-driving units to give flexibility. I can't remember the exact number off hand, but there will always be a small handful of trains with at least one cab in the middle. There are 175 A-B units and 165 B-C or B-D units, so there would be 5 A-B units in the middle if all units were formed into 8-car trains. Edit: I've just looked at some of my videos, and 91341 was formed in the middle of a train in October 2011, and 91249 in November 2012. I've also found a thread on another forum from June 2012, when units 91177, 91311 and 91341 were said to be always used in the middle with some equipment removed from the cabs. |
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hobbayne
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Post by hobbayne on Dec 7, 2014 11:24:30 GMT
LUL dont really like to use an A car in the middle of the train as it wastes a lot of space. As a Central Line T op I cant stand them. Especially when reversing in a siding changing ends it really slows you down fumbling for a j door key.
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metman
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Post by metman on Dec 9, 2014 13:02:09 GMT
Yes I can imagine that is a bit of a hassle. Having said that would the t/op need the J door key to get into their new leading cab anyway?
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hobbayne
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Post by hobbayne on Dec 9, 2014 14:57:30 GMT
Yes I can imagine that is a bit of a hassle. Having said that would the t/op need the J door key to get into their new leading cab anyway? Yes, but its usually in my bag or pocket. Its just that I dont often expect them to be there, so its a nuisance to me to be confronted by one. |
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Post by Deleted on Dec 12, 2014 20:56:52 GMT
It reminds me of the D stock, which sometimes has a double cab ended unit coupled up to a single cab end unit, giving a spare cab in the middle.
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Post by melikepie on Dec 12, 2014 21:06:58 GMT
If any train anywhere is driving from the middle, how can they possibly see where they're going? Do they have a computer screen?
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Post by Deleted on Dec 12, 2014 21:18:30 GMT
It reminds me of the D stock, which sometimes has a double cab ended unit coupled up to a single cab end unit, giving a spare cab in the middle. Yeah, it's much more common with the D stock and used to be very common with the old Cs and As, too, but with the 1992 stock it's pretty unusual. Not unheard of, by any means, just comparatively rare. If any train anywhere is driving from the middle, how can they possibly see where they're going? Do they have a computer screen? No train is driven from the middle cab. It's possible to drive in reverse from the back cab, if the one on the front has a really big problem (I think a main line burst on the leading car might occasion this). This is done by having a person in the front cab giving instruction to the T/Op in the rear cab via the cab to cab. But you would never drive a full train from the unit in the middle as far as I know. You could, of course, split the train in the depot and then drive the two new halves separately and then you could drive from the cab that was in the middle, but is now at the front of its own half a train (as long as it's not gutted), but you wouldn't drive the full train from the middle with carriages in front and behind. No, it's just that sometimes trains may be formed with A units (units with a driving cab) in the middle of the train. I gather a slight surplus of A units were built because of the obvious large problems that could be caused by damage to a single A unit. Spare A units are good, cause you need an A unit at each end, so if you only have the bare minimum of A units and one of them goes wrong, you won't be able to substitute any other unit in its place and you'll lose an entire train. |
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Post by whistlekiller2000 on Dec 12, 2014 21:34:34 GMT
If any train anywhere is driving from the middle, how can they possibly see where they're going? Do they have a computer screen? Hmmmmm...........possibly..........Captain Scarlet drove his Spectrum Pursuit Vehicle at ridiculous speeds whilst facing backwards, and he was a puppet, so I doubt it'd pose too much of a problem for a suitable qualified human in a train. |
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Post by norbitonflyer on Dec 12, 2014 22:57:29 GMT
used to be very common with the old Cs and As, too, Since all C stock units were single-ended, and you needed three of them to make a six car train, there was always a cab in the middle. Likewise all A stock units were double ended, so there were always two cabs in the middle - although some of them didn't work. |
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rincew1nd
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Post by rincew1nd on Dec 13, 2014 0:15:16 GMT
Yeah, it's much more common with the D stock and used to be very common with the old Cs and As, too, but with the 1992 stock it's pretty unusual. Not unheard of, by any means, just comparatively rare. I spied one today, managed to grab two snaps which are here and here. |
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Post by Deleted on Dec 13, 2014 0:42:10 GMT
Yeah, it's much more common with the D stock and used to be very common with the old Cs and As, too, but with the 1992 stock it's pretty unusual. Not unheard of, by any means, just comparatively rare. I spied one today, managed to grab two snaps which are here and here. Nice  Is that Liverpool St, out of interest? |
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rincew1nd
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Post by rincew1nd on Dec 13, 2014 1:31:08 GMT
What do you think this is, the daily quiz?  |
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Post by Deleted on Dec 13, 2014 3:38:24 GMT
What do you think this is, the daily quiz? Hehe No - although, if I'm right, can I carry my points over to the daily quiz...? |
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metman
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Post by metman on Dec 13, 2014 22:19:25 GMT
Yes and the 73 stock is the same although there is a much greater chance of finding this in both stocks as there is quite a large number of double cab units in the fleet to provide flexibility. The D stock for example has 65 west facing and east facing single cab units with 20 double cab units. These form 75 trains so in reality 20 of the 75 trains will have a middle cab.
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Post by Dstock7080 on Dec 15, 2014 11:39:43 GMT
Purely by accident I travelled on 91341 today, as the third car of an EB train.
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hobbayne
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Post by hobbayne on Dec 15, 2014 12:35:32 GMT
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Is that Liverpool St, out of interest?
