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Colin Rosenstiel · February 15th 08, 12:59 PM posted to uk.transport.london

In article
,
(Andy) wrote:

On Feb 14, 11:48*pm, (Colin Rosenstiel) wrote:
In article

,

(Andy) wrote:
On Feb 13, 11:56*pm, asdf wrote:
On Wed, 13 Feb 2008 00:04:19 GMT, wrote:
I can't remember what kind is at Gunnersbury etc, but on the
Bakerloo shared sections, I think the markers are NR style.

For both the Underground and Overground, right?

The Overground has "3 car stop" and "6 car stop" signs (or "S
car stop" at some stations instead),

I thought the "S car stop" was what they used for both on the
District, though I could be wrong.

though 6 car trains never run (and it
may not even be possible).

Why would it not be possible?

The power supply may not be able to cope with the current drawn
by a 6-car 313 accelerating.

In the past, there have been 6-car 313s on the Euston - Watford DC
lines. I can certainly recall them being used at weekends when
there
were blockades on the WCML, although not recently.

As I said, there are plenty of 6-car 313 trains on the line they were
delivered for, the GN.

Ahh, but the electrification of the GN line was designed for 6-car 313
formations. The Euston DC lines electrification was designed for the
mix of Bakerloo and mainline stock. The previous generation of units
(Class 313) only had one motor coach with 4 x 185 hp motors (according
to my old Combined Volume) whilst the class 313s have two motor
coaches with 4 x 110 hp motors (from the same source). So a single 501
had a power rating of 740hp, whilst a single 313 has 880hp. This is
nearly 20% more power and 50 % more motors. The potential problem on
the DC line wasn't the length of the train, but whether the power
supply could deal with the higher current drawn by a 6 car 313
(especially on starting) compared to a 6 car 501 in days gone by.

NB, I know that hp is hard to relate directly to the current drawn by
the unit, but the comparison still shows the potential problem.

And the 1938TS had (IIRC) 2 x 168HP motors per motor car of which there
were 5 per train, total 1680HP. I also have a feeling that 501s ran in
pairs on occasion.

--
Colin Rosenstiel