This has been discussed a few times before, for example here:
Cedric Martindale founder of CKP Railways reports that the bid documents that he submitted with the support of Allerdale District Council and 4 local MP's is one of only 10 out of 60 submissions that is to be taken forward immediately by Department for Transport to the next stage (source...
www.railforums.co.uk
Back then (4 years ago) I estimated Penrith - Keswick alone to be in the range £500m-£700m. It will be more now. Going all the way to Workington will be well north of £2bn. To put it in context, it’s about 30% longer than EWR Eastern Section which is in the order £3bn. And EWR is mostly on easy ground, and very specifically not through a national park.
Worth noting that this went absolutely nowhere in the Restoring Your Railway programme.
Absolutely slam dunked.…. straight into the bin.
It is *very* convenient. In my opinion rather more convenient than the train would be, as it actually goes to Keswick town centre, unlike the railway. And at the Penrith end drops you right outside the front door of the station - it‘s a shorter walk from bus to train for southbound passengers than it would be for an imaginary Keswick train to train.
For the price of a (proper) feasibility study that would inevitably tell you it has no business case, you could double the bus service for several years and make every other one a very limited stop Penrith - Keswick - Cockermouth - Workington which would knock chunks of time off it.