Clive D. W. Feather wrote:
In article , Dave Arquati
writes
The current service pattern fails at Camden when a train from either
southern branch destined for a particular northern branch reaches the
junction at the same time as a train from the other southern branch,
destined for the same northern branch - one of the trains must wait
and blocks trains behind it (destined for the other branch).

Not quite: I *think* that the junctions on the Charing Cross branch
are far enough south that a train can stand between the divergence
and the convergence with the Bank branch. Thus if you have one for
Edgware on each route, you let the Bank one in and hold the CX one; a
following CX-Barnet train can then run. Similarly in the southbound
direction.

The diagrams at http://www.geocities.com/athens/acro...9/ltcamden.jpg
and http://www.geocities.com/athens/acro...camdenjunc.gif don't
prove you're right, but they do prove you haven't got it the wrong way
around!

"Clive D. W. Feather" wrote in message
...
In article , Dave Arquati
writes
The current service pattern fails at Camden when a train from either
southern branch destined for a particular northern branch reaches the
junction at the same time as a train from the other southern branch,
destined for the same northern branch - one of the trains must wait and
blocks trains behind it (destined for the other branch).

Not quite: I *think* that the junctions on the Charing Cross branch are
far enough south that a train can stand between the divergence and the
convergence with the Bank branch. Thus if you have one for Edgware on each
route, you let the Bank one in and hold the CX one; a following CX-Barnet
train can then run. Similarly in the southbound direction.

The signal diagrams at
http://www.trainweb.org/tubeprune/Ca...wn-lct5-10.gif appear to
confirm this is possible.

Peter Smyth

Peter Smyth wrote:
"Clive D. W. Feather" wrote in message
...
In article , Dave Arquati
writes
The current service pattern fails at Camden when a train from either
southern branch destined for a particular northern branch reaches the
junction at the same time as a train from the other southern branch,
destined for the same northern branch - one of the trains must wait and
blocks trains behind it (destined for the other branch).
Not quite: I *think* that the junctions on the Charing Cross branch are
far enough south that a train can stand between the divergence and the
convergence with the Bank branch. Thus if you have one for Edgware on each
route, you let the Bank one in and hold the CX one; a following CX-Barnet
train can then run. Similarly in the southbound direction.

The signal diagrams at
http://www.trainweb.org/tubeprune/Ca...wn-lct5-10.gif appear to
confirm this is possible.

Ah, ok, my mistake. However, unless I've misunderstood that diagram,
whilst NB trains from CX can be held without delaying following trains,
the same is not true for NB trains from Bank.

In any case, segregating the branches would prevent such dual arrivals
happening in the first place, so as long as the trains are spaced far
enough apart to allow for the appropriate dwell time at Camden Town
platforms, there would be no need for them to stop at the junction at all.

Would ATO be sophisticated enough to adjust train speeds on the central
branches to avoid dual arrivals?

--
Dave Arquati
www.alwaystouchout.com - Transport projects in London