On Mon, 17 Nov 2008 05:01:55 -0800 (PST), D7666 wrote:

Bellingham (if the sidings are retained) look difficult to
extend to full 12 car.

I'm puzzling over St.Albans for similar reasons.

The south end is already extremely narrow on the island platforms 2/3
- it is so narrow it would never get through safety rules if this were
a new station today. So if extending that way they would need to
significantly widen as well as lengthen ... and I think that option
has effectively been cut off by the new building work outside the
railway on the Up side.

The north end has the present 8car turnback siding in immediately off
the north end of the platforms. For the turnback to be retained to be
of any operational use it too would need extending to 12 cars ... and
as reported in uk.railway previously it is only just dead 8car now, so
probaly needs extedning by 4-and-a-bit for SPAD mitigation. So if the
platforms are extended north by 4car, the buffer stops at the extreme
end of the turnback needed shifting north by a bit more than
equivalent to 8 car lengths, and here you are well into a deep
cutting.

Even staggering the extended platforms does not work for combinations
of the above reasons.

I am assuming therefore that St.Albans loses its turnback facility ???

Surely the turnback siding doesn't have to be immediately outside the
station? It could, for example, be moved a few hundred yards down the
line.