QUOTE (hairyhandedfool @ 3 Dec 2011, 09:49)
<{POST_SNAPBACK}>I'm not entirely sure what you mean by ex-midland mainline, but I know that West Hampstead Thameslink to Bedford inclusive currently have Platform 1 for the Up Slow (US). Generally speaking platform 2 is for the Down Slow (DS), 3 for the Up Fast (UF) and 4 for the Down Fast (DF), the exceptions being Bedford (3 is on a loop, there is no platform for the UF) and Luton (2 is for a loop, 3 is for the DS, 4 is for the UF and 5 is for the DF). At Kentish Town 1 is for the Up Moorgate, 2 is for the Down Moorgate, 3 is for the US (reversible) and 4 is for the DS (reversible).
'Ex Midland mainline' means exactly how it reads, as in the line from St Pancras to Nottingham/Sheffield is the mainline of the former Midland Railway, and has always been referred to as the 'midland mainline', even before privatisation...
The stations that are still open along the MML have their platforms numbered with platform 1 being the platform nearest the main station buildings(an exception being Nottingham, platform 1 at Notts is on the Station street side of the station, which is where the main buildings used to be before the Midland rebuilt the station in 1908).
At Bedford, platform 1a was added after the station was rebuilt, to accommodate the Bedford-Bletchley services. There is no Up fast platform, as Up trains can use platforms 1, 2 and 3 without coming into conflict with any other trains. The Down fast platform, number 4, was added also at a later date, so that trains on the Down fast didn't cause any conflicting moves with Up trains. Bedford station used to be closer to the overbridge at the south end of the site, but was moved further North when rebuilt as the original layout was too cramped.
Luton was rebuilt by the LMS in the 1930's, I'm not aware of the original station's platform numbering though.
Kentish town's platform 1 was where the main buildings were situated before they were demolished.
Chris