Because Skipton-Colne is along a valley, but there is a ruddy great range of hills between Keighley and Colne where a 6 or 7 miles long tunnel would be needed and twice the distance so would be at least double the cost. It would also bypass the settlement of Skipton.
Where to start?
Well, Skipton is in the same valley as
Keighley - Colne is in a whole other valley (the Colne flows westwards, it feeds into the Pendle Water which feeds into Lancashire's Calder - not to be confused with the one through Halifax - which feeds into the Ribble), whereas the Aire flows eastwards down through Skipton/ Keighley/ Leeds - so the idea that
Colne and Skipton are "along a valley" seems a bit of an "unusual" justification.
Colne - Cross Hills would be shorter than Colne - Skipton, and would mean that Colne - Leeds/Bradford passengers would have a much faster journey than going all the way north to Skipton to come down the Aire Valley - since a fast link to Leeds/Bradford is meant to be one of the main justifications for regenerating Colne and therefore building a line.
And Skipton is hardly a major place.
But the whole thing is a non-starter.
It always conveniently ignores the fact that there's a regular service from Blackburn/ Burnley to Halifax/ Bradford/ Leeds (i.e. it's not as if East Lancashire has no trains to West Yorkshire - it's only the top end of the valley that lacks such a link.
But also, where's the spare capacity on the Aire Valley for Colne passengers/trains (given that Network Rail are struggling to build platform extensions to permit six coach EMUs just to cope with existing demand)?
There's a lot of fluff about freight but where is the freight going to go at each end?
The SELRAP people claim that they can build it for £100m but also like to claim that this will be a major transpennine route (which presumably doubling the line from Colne down the valley to Burnley, electrifying all the way to Preston etc?).
IMHO the best hope for a line from Skipton to Colne would have been if the entire Colne branch had been closed - we'd now see people demanding that Colne be reconnected to the railway, that a line from Colne to Burnley would justify a frequent service (given that the parallel bus route is pretty frequent) - there'd be some kind of political case for building a line to an economically deprived area... but instead the Colne branch survived and gets an average passenger loading of twenty-something - i.e. suitable for a minibus rather than heavy rail - so there's no way of claiming a success.
Then there's the times. Based on existing timings (and if you allow twenty minutes for Skipton - Colne) then Keighley - Manchester will still be faster by changing at Leeds onto a frequent TPE service than going north to Skipton and down through Colne/ Burnley/ Blackburn.
Leeds - Skipton is around forty five minutes - whereas it's marginally over an hour for Leeds - Burnley - so (adding on twenty minutes for Skipton - Colne) given the existing fifteen from Colne to Burnley then it's always going to be a lot slower for Leeds - Burnley passengers (than the existing route via Halifax).
The simpler thing would be to extend the current (Rochdale) - Manchester - Bolton - Blackburn service to Burnley and Colne (replacing the Blackpool South stopper), ticking the "economic regeneration" box by giving Colne an hourly link to a big city with no infrastructure required... but I guess it's always more fun to suggest re-opening an abandoned line and spending hundreds of millions of pounds having trains running through empty countryside than just rejigging existing diagrams to connect a small town to civilisation (without needing any additional infrastructure).
Or, if giving the people of East Lancashire a better service to Leeds is that important then simply extend the hourly Hull - Halifax service through to Burnley and Blackburn - you'd need an extra DMU or two to provide this but that's hardly breaking the bank when the alternative is hundreds of millions of pounds.
Always the same though - we'll be having this argument in a decade's time because the True Believers will never give up hope. And, given that politicians want to attract the votes of nostalgists across the country (given the large numbers of pensioners who vote) then there'll always be long lists of potential re-openings every few years, SELRAP will always feature because running trains through the North Yorkshire countryside will appeal to people (rather than doing something uglier and significantly more practical like focussing attention on places like Skelmersdale).
