"Ben Nunn" wrote in message

"Peter Smyth" wrote in message
...

If one loop goes HX-T4-T123-HX and the other goes HX-T123-T5-HX,
then the diagram will need to resemble a pair of testicles at the
end of the line, no?

T5 will not be on a loop. Some trains will go HX-T4-T123-HX as now
and the others will go HX-T123-T5(reverse)-T123-HX


So how will that work with the two platforms at T123? Will one be used
exclusively for London-bound trains that have gone round the loop,
and the other for bi-directional trains on a single track extension
to T5?

Or will it be one platform be for T5 only, and the other for both
sets of London-bound trains? (which would make more sense to the
traveller, but be logistically more difficult to implement, and
result in a bizarre station where twice as many trains went in one
direction as t'other.)

I had assumed that it was a double tunnel from T123 to T5, with two
platforms at T5. I don't think a single tunnel could maintain the
required service frequency.

The T4 loop would connect with the eastbound (northern) tunnel just
before the T123 station. To do this, the rebuilt loop will presumably
have to dive under the west-bound (and maybe both) tunnel, whereas the
current version is on the level -- hence the long closure.