District S8s?

[Deleted]

Would it be possible to run S8s on the District - given that 8-car sets ran back in the days of R stock? Assuming minor works such as repositioning barriers and signals by a car's length, of course, but not platform lengthening. If so, was it considered as a means of increasing peak capacity when procuring the Ss? The stretch through Victoria seems to be well overfull in the peaks and I've taken to walking to St James Park now rather than waiting several trains to go the one stop...

[Colin]

Whilst some platforms are already long enough, some are not - the obvious starter for ten is Gloucester Road westbound. Granted selective door opening can be employed though.

The District was always going to get S7's so I doubt any consideration at all was given to squeezing in S8's.

You talk about 'minor works' but there's no such thing on the railways - simply moving a barrier two foot can cost hundreds of pounds. S8's are considerably longer than the current D stock's - as it is there's a lot of costly repositioning work going on just cos S7's are a little bit longer - I can well imagine the scope of things affected by running S8's would affect not just the repositioning of barriers, walkways & signage but may also go on to affect things like the signalling system too. Now that is seriously big bucks.

[mrjrt]

I think when this cropped up before I suggested a gradual programme of lengthening whenever possible - i.e. Blackfriars would be a great example, as would any future major works on Tower Hill or Mansion House re changing the bays. It's a disgrace really that the District still isn't running trains with the same capacity as the Met after all these years!

[castlebar]

mrjrt, Don't start me off. There are still those around who think that if it worked well enough in 1912, if it ain't broke don't fix it, so it will be fine for 2012.

Never forget that no politician, or "Head of planning", ever got fired for NOT spending money.

[Ben]

One suspects that of the many reasons why something like this doesn't happen, its only the minority that have anything to do with what a railway is really capable of.

Lengthening was done before on this section when each station came up for rebuilding. 7 car S stocks will eventually serve 6 car platforms, so a future precedant might exist at some point?

Put in an FOI request maybe? It'll probably force someone involved to put more time and effort into creating an answer than when (or if) it ever came up before internally.

[metman]

The problem on the District is that the platforms can only really handle 7 cars of 51ft stock. When 8 car R stock was used, the ends of the cars would be in tunnel at both ends. The guard would give the starting signal. Now the driver has to check personally. The new S Stock has 54-52 foot long cars so a lot of civil engineering work would be required. The money is not available for this. SDO could be used but over an entire section it isn't practical. Long delays are likely as people would have to shuffle along a crowded car added to dwell times. Its not so bad on the few platforms between High St Ken and Baker Street but over the Southern Circle is pushing it.

[Deleted]

Frankly, 6-car D stocks can get very crowded, even on weekends,(usually the only time I'm on the tube.)
I actually don't imagine S7 will be much better, becaues of the carriage connections. The flow of passengers from a crowded end to an empty end, then back again once the empty end becomes crowded will make things critical. Actually, I don't think S8 would make much of a difference either. Obviously 10-car trains aren't an option, but mabye a totally different fleet for the District to control it would have been justified?
That said, the Circle isn't immune, and that wouldn't have got anything apart from S7s, no matter what.

[superteacher]

Dec 14, 2011 19:25:28 GMT @thecatapulttv said:

Frankly, 6-car D stocks can get very crowded, even on weekends,(usually the only time I'm on the tube.)
I actually don't imagine S7 will be much better, becaues of the carriage connections. The flow of passengers from a crowded end to an empty end, then back again once the empty end becomes crowded will make things critical. Actually, I don't think S8 would make much of a difference either. Obviously 10-car trains aren't an option, but mabye a totally different fleet for the District to control it would have been justified?
That said, the Circle isn't immune, and that wouldn't have got anything apart from S7s, no matter what.

The S7's have double doors compared to the D's single doors - that should make a difference in itself.

If people know that they are able to walk through a train once they've boarded it, then they will be less likely to stand by the door which they believe leads them to the least crowded carriage. SO this should also speed things up.

Finally, the frequency will increase once the resignalling has been completed.

[t697]

Dec 30, 2011 18:40:21 GMT superteacher said:

The S7's have double doors compared to the D's single doors - that should make a difference in itself.

If people know that they are able to walk through a train once they've boarded it, then they will be less likely to stand by the door which they believe leads them to the least crowded carriage. SO this should also speed things up.

Finally, the frequency will increase once the resignalling has been completed.

Well, S7 has 21 double doorways per side of the 117m train. D78 has 24 wide single doorways per side of the 111m train. You certainly don't get double throughput with a double doorway. There's a bit more circulating space in S7 doorways. At a few D78 route stations one doorway will stay closed on S7 due to the extra train length. Will all that overall reduce dwell times? I think it will, but debate on!

[superteacher]

Dec 31, 2011 17:06:21 GMT t697 said:

Dec 30, 2011 18:40:21 GMT superteacher said:

The S7's have double doors compared to the D's single doors - that should make a difference in itself.

If people know that they are able to walk through a train once they've boarded it, then they will be less likely to stand by the door which they believe leads them to the least crowded carriage. SO this should also speed things up.

Finally, the frequency will increase once the resignalling has been completed.

Well, S7 has 21 double doorways per side of the 117m train. D78 has 24 wide single doorways per side of the 111m train. You certainly don't get double throughput with a double doorway. There's a bit more circulating space in S7 doorways. At a few D78 route stations one doorway will stay closed on S7 due to the extra train length. Will all that overall reduce dwell times? I think it will, but debate on!

I certainly wouldn't argue that double doorways lead to double throughput, but operationally single leaf doors were a mistake which is still regretted!