In message , Roland Perry
wrote:
It currently has four "single lead" junctions (a, b and c).

Only the Peterborough direction has a full two-track junction.

https://goo.gl/maps/3JziEjRARYF2

So it's like this:

Ely ------------------------------------ Peterborough
\
Ely ---------a-------------------------- Peterborough
\
*
\
b------c--------------- Kings Lynn
\ \
\ -------------- Kings Lynn
\
d------------------ Norwich
\
----------------- Norwich

Actually, a+c is a single lead junction, as is a+d. b is just a single
track junction.

A "single lead" junction consists of a crossover between the two main
tracks, a turnout from one track to the branch, and points merging the
two tracks of the branch.

As is fairly obvious, places like "*" are a monster bottleneck.

Actually, even worse is when the points just to the left of "a" fail in
the diagonal, rather than the straight position. (I've not seen it
happen in real life, but I have in simulation.)

If anyone wants to experiment with how this layout works, let me put in
a plug for SimSig Cambridge (http://www.simsig.co.uk).

--
Clive D.W. Feather | Home:
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