On Sat, 21 May 2005, Dave Arquati wrote:

Tom Anderson wrote:
On Sat, 21 May 2005, TheOneKEA wrote:

Tom Anderson wrote:

I might have lost the plot, but that seems to make no sense whatsoever -
making the line longer wouldn't have capacity implications. You could run
trains at exactly the same frequency (if you had a few more), so as far
as Brixton is concerned, it wouldn't be any different. Or am i being
stupid?

Extending the line and adding more stations increases the number of
passengers that the line must carry.

Right.

To ensure that loadings remain even, train frequency must be increased to
compensate, which is the problem at hand.

Okay. I don't understand that - why does the frequency have to increase?

Because, given that the vast majority of passengers are travelling to the
central area (say Victoria - KXSP), the passengers from the new, extension
stations are using capacity in the central area which isn't available.

Aaah! I see. Yes, that's rather obvious when you put it like that, sorry.

The Victoria line is essentially full at the moment.

Next question, then - how come? It has a pretty decent 28.5 tph, it's the
shortest proper line in the whole network, and all but one of its stations
are on other lines as well!

For northbound trais to be be full at Victoria, Brixton, Stockwell,
Vauxhall and Pimlico would have to be generating as many passengers as all
the Northern line stations from Morden to Kennington put together, or the
Piccadilly line stations from Cockfosters to Caledonian Road. I don't know
those areas terribly well, and i realise that at least some of them are
very densely populated areas, but that seems quite surprising. Is it
because there are few people getting off the line before central London? I
guess a lot of Picc passengers switch to the Vic at Finsbury Park, and
perhaps Northern passengers to the Vic at Stockwell! Or is the Victoria
line picking up a lot of passengers from the suburban railway network?

tom

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