"asdf" wrote in message
...
On Mon, 18 Jul 2005 19:38:12 +0100, "Andy H"
wrote:

Two points.
Firstly, LT trains work in the same way and I am not aware that
they have
had problems.
Secondly, Once a tripcock is struck it remains in the up
position until
it
is reset when the unit is uncoupled so the rear unit tripcock will
only be
hit once per period of time that the unit is coupled as the non
leading
unit.

The only difference being that the LUL trains will get strike the
first
signal they encouter leaving the depot at 10mph whilst the Chiltern
units
similiar first experience will be a signal at 75mph!

Surely they'd be moving slowly, having just stopped at
Amersham/Harrow-on-the-Hill? In any case I don't think 75mph is
permitted on the LUL track!

Towards Amersham, from Aylesbury, the trains enter LUL track at,
presumably, 60mph at "Mantles Wood Junction".
Where is the first LUL signal with trip after the junction and before
Amersham station, presumably before the siding line into the main
london bound platform at Amersham... but how close, as the trains will
still be travelling at some speed at that point.