[originally posted on uk.railway]
[x-posted to uk.transport.london]

On Jun 29, 2:07*pm, Ben wrote:
I'm trying to understand what happens to FCC services north and south
when the Thameslink core closes. Do the FCC services from Bedford,
Luton and St Albans share the 4 EMT platforms at St Pancras? I
understand that the Sevenoaks services are diverted to Victoria and
the Wimbledon & Sutton trains go to London Bridge but what happens to
the Brighton services? Are the services modified in any way or do the
standard patterns operate?

Re the northern Thameslink services from St Pancras - my understanding
is that during the weekend closures of the core Thameslink route,
initially the FCC Thameslink trains were using the high-level (EMT)
platforms - indeed I saw this with my own eyes - but then there were
alterations made to signalling on the low-level route (I think it was
the installation creation of bi-directional signalling but I'm unclear
on the details) that has enabled them to use the low-level platforms
at St P (i.e. the normal Thameslink platforms), which is what they now
do.

Brighton services go to and from London Bridge, from the terminating
platforms (i.e. not from the usual through platforms 1-6).

The Wimbledon & Sutton situation is actually a bit more complicated
(and the reason for the crosspost to utl) - some of the time it seems
trains leaving London Bridge navigate the loop clockwise, then call at
Tulse Hill again before terminating at Herne Hill - then do a return
trip to London Bridge, going back anti-clockwise this time. But at
other times other arrangements apply. There's also a range of rail
replacement buses thrown in for good measure too.

I must admit that when I noticed this situation a good while back and
thought I should try and figure it all out some time, but I'm afraid
the intellectual exercise defeated me a little - not that I tried
*that* hard though! But the information FCC provides is pretty shoddy
- mentions of "Herne Hill/Tulse Hill" almost as a single entity are
very far from being clear, and I suspect many potential punters from
south London don't bother and find other means of making their
journey.

Take a look at this PDF document on the FCC website and see if you
think what it says about Wimbledon & Sutton services is clear and
easily intelligible:
http://tinyurl.com/mah7q4

Maybe I'm just a bit stupid?