Thanks for that info, really interesting. Just a point of pedantry though, wouldn't Blackburn services (both to and from) have had to use the modern-day platforms 1 and 2? There's no access available from p4 and I would assume such a connection would be removed in such a remodelling as took place in '85.
Not so - this has only been the case since the most recent re-modelling sometime in the 80s/90s (cant remember when exactly.) The current Bolton Trinity Street station was totally rebuilt at the start of the 20th century (1904 I think.) It featured two long island platforms: all Up trains (towards Manchester Victoria) used the current platforms 1 and 3; all Down trains used the current platform 4 and the disused face behind - where the car park now is. Between platforms 3 and 4 there is still a wide gap where the Up and Down Through lines were located. Part way along both the current platforms 3 and 4 were double x-overs between the platform line and the adjacent fast line, which allowed two trains to use both platforms at once.
Services
from Blackburn generally used platform 1 - as now, but could (and did) use the current platform 3. All services northbound used the present platform 4, but Blackburn-bound trains stopped south of the x-over, before departing around the curve into Bradshawgate Tunnel via a now lifted track. Trains from Victoria to Wigan Wallgate/Preston destinations either used the same southern part of the present platform 4 or came in on the fast and crossed over onto the platform road and used the now disused part of the platform where it curves around under Trinity Street bridge towards Morrisons.
Pic: (courtesy of Flikr)
http://www.flickr.com/photos/ingythewingy/4483884896/
The line immediately in front of the 47 is the lifted track from the present platform 4; the platform end just visible is the present platforms 1/3, with platform 4 visible behind the train. Between is the Down Fast.
And of platform 4 (again courtesy of the same Flikr account):
http://www.flickr.com/photos/ingythewingy/4483234855/in/photostream/
The pointwork for the x-over is just visible on the right-hand side.
The present bay platform 2 was rarely used until fairly recently. It (and a similar bay at the southern end of the opposite island) were used by the Bolton - Bury Knowseley Street - Rochdale (and beyond) services and the Railmotor services to Radcliffe on what is now the Metrolink to Bury.
As regards Blackburn-bound trains stopping, so far as I am aware all regular passenger services called at Bolton Trinity Street en route - even the Midland Railway's Pullman trains from Manchester to Scotland. They even called at Darwen!
The route between Blackburn and Bromley Cross was indeed singled (apart from the passing loop at Darwen) as part of the Preston PSB works in the early 70s. The line from Bromley Cross continued as double track all the way into Bolton until the remodelling/resignalling works that took place in the late 80s, when Manchester Piccadilly's area of control extended northwards to Blackrod Junction and Bromley Cross.
Incidentally, it was also at the same time that Bolton West Junction box closed - the first fully electro-pneumatic installation in the country. Personally I rather miss the hiss of compressed air every time the points/signals changed!
