On 30/01/2013 23:36, Peter Smyth wrote:

But they did improve the signalling during the closure - hence why they
can now run five trains at once instead of four trains.

As for increasing train lengths, I suspect the main constraint is the
very limited depot space available for stabling rather than the actual
platforms.


My understanding is that the signalling was replaced like-for-like
rather than there being a fundamental redesign.

I believe 5 car trains of the old (1940) stock were possible, but the
individual cars were slightly shorter than those of the 1992 stock, and
the platforms at Bank have since been reduced in length to give longer
safety overlaps.

Perhaps the Southern railway had it right with the 1940 stock, with a
mixture of motor and trailer coaches that could be remarshalled as
needed so a failure on one car wouldn't take out a whole train set!