Thanks Dougie. I've just been having a look at the road on old-maps.co.uk. You're right; it seems to disappear (or at least the bridge and eastern end of it do) in the late 1960s, I guess when work was getting underway to transform the old Garswood Hall Colliery site. There are still some traces of the road in the field by Landgate Lane - I previously mistook them for remnants of the old railway from Pemberton but it's clear from the maps that the railway arched southwards to make for a smooth connection with the Wigan-Liverpool line. I'll look out for traces of the bridge next time I'm over that way.

As for the proposed new road I think it's more likely that they'll excavate the whole area and then start again from scratch. I recall reading in some council document or other that parts of it may be contaminated due to domestic refuse etc being used to fill in the old railway cutting.

Town: Ashton