The back story.....
Decades ago I got interested in railway history in the north of England, and in particular the various madcap schemes of the 1845/46 Railway Mania. As a result I came across the proposed Liverpool, Manchester & Newcastle-upon-Tyne Junction Railway which planned a line from Preston along the whole of the Ribble valley and tunnelling through the hills to get to Hawes and thence across to Darlington ; with connections at various points to existing or planned lines. The company merged with another scheme, adopted their slightly different route, and received Parliamentary approval, but of course nothing was actually built.
My assumptions start with a 'what-if' the Act had authorised the original route and that it had actually been built. Second 'what-if' is that local pressure, which did exist at various stages throughout the 19th century, saw a branch line built from Hawes down Garsdale to Sedbergh, and a little later a line continued to a southward-facing connection with the Ingleton line to the south of the real Sedbergh station. Later still a narrow gauge line was built up Dentdale to serve the various quarries; and of course also to serve my interest in all things narrow-gauge!
Hope that's enough to give a general flavour of where I'm coming from - ask away if anything doesn't make sense.