On 22 Feb, 19:19, Charles Ellson wrote:
On Thu, 21 Feb 2008 16:05:57 -0800 (PST), MIG

wrote:
On Feb 22, 12:00*am, "John Salmon" wrote:
"Charles Ellson" wrote

Reversal can also happen with C stock that doesn't stay on the same
line service all day (i.e. Circle Wimbleware or Circle
Hammersmith and City).

That would not reverse them, unless they go 'off route' to run direct
from Aldgate East to Tower Hill, or Gloucester Road to Earls Court.

C stock always had universal couplers though, so that must have been
the assumption.

With the amount of traffic via the relevant junctions it can be
reasonably anticipated that the occasional points failure is going to
result in trains being sent the wrong way on some occasions thus
making handed coupling an undesirable feature WRT the possibility of
it not being impossible that at the same time a train could fail and
require the coupling of a following train for assistance. This leads
onto the question of whether or not C and D stock can assist each
other but if they can't then it still reduces the need for a coupling
adaptor if the following train is the same type.

I would assume not. D stock has different A and D couplers and C
stock has universal couplers.

The first twenty D stock units had cabs at both ends so that they
could work either end of a train without being reversed, and the
subsequent 130 or so had a cab at one end. There's two units in a
train.

I was thinking of reasons why the C stock wouldn't have lined-up
diagrams. Firstly, east and west would be reversed on opposite sides
of the Circle anyway, without reversing the train.

Secondly, a C stock train is made of three single-ended units. Two of
them have to face outwards (therefore in opposite directions) and the
middle one can face either way. It would seem to be very complicated
to have half the middle units only able to face one way as well as the
end ones.

You would either have to have two different arrangements, and the
middle units not line up the same way in depots (if that mattered), or
else have all the middle units face the same way, in which case two
thirds of units would have one kind of diagram and one third the
other, and only one third of cabs would be usable at one end.