I spent many a weekend travelling around the area on a Merseyrover ( early 70's ).
I think, if I remember correctly, until 1972, trains were routed into the East Lancs platforms via Todd Lane Jnc.I can remember taking this route and shortly afterwards, following closure of the East Lance platforms walking the partially lifted trackbed from Preston to Bamber Bridge. The track was double from Midge Hall on both routes into Preston. There was a signal box at Midge Hall controlling the level-crossing and I've photos showing the track double at least until 1976.
I had wondered, so thanks for that semi-confirmation. I know Moss Lane Junction box remained open until 1972, so presumably one of the two routes (either Moss Lane Junction - Lostock Hall or MLJ - Farington Curve Junction) must have been largely abandoned in the 1970-72 period.
There was indeed a signal box at Midge Hall: a L&Y one on the north side of the level crossing until 1972, which was replaced by the current BR box as part of the Preston re signalling. Double track was abolished in, I think, 1983 between Midge Hall and Preston, though it wasn't lifted until about 1990, and the chairs and sleepers are still down between the site of Moss Lane Junction and Farington Curve Junction.
Don't suppose you have any photos of the line at the time...?