Living very near to the Dore triangle of junctions I'm very aware that the most critical point is currently Dore West and that's where most benefit will come after completion of the Hope Valley Capacity Scheme.
There's a misconception that all trains run south towards Chesterfield. They don't, although many are routed through Sheffield to get to Barrow Hill.
I've taken a random RTT listing of all freight trains across that junction last Wednesday, a fairly typical day, see;
https://www.realtimetrains.co.uk/se...3-31/0000-2359?stp=WVS&show=freight&order=wtt
The low number of freight paths actually used is the first thing that may strike some. Many are apparently duplicated. That's because the paths along the Hope Valley to and from the quarries and cement works spread out around the country so a variety of destination options have to be planned in.
However, detailed examination over a long period would reveal that a significant number of these paths are never, or very rarely, used. There does not appear to be a shortage of freight paths now going east, let alone after the scheme works have been completed.
Planned freight paths going west through Chinley show an even greater number of unused paths, see;
https://www.realtimetrains.co.uk/se...3-31/0000-2359?stp=WVS&show=freight&order=wtt
On that evidence can we justify building a new line?
At present output of limestone is increasing. As the years go by I strongly suspect there'll be increasing environmental objections to further extraction licences. There will be a limit as to how much of the Peak District can be exported around the country before there are too few peaks left to be acceptably mined. I say that as one brought up in South East Northumberland where I'd not have believed that coal extraction would have stopped in my lifetime.
There's concern about cycle traffic between Matlock, Bakewell and Buxton. Anyone using the A6 will not be the same sort of cyclist normally using the Monsal Trail. The nature of the A6 is such that cycle traffic is very light, usually only ridden by the strongest long range cyclists due to the gradients, narrowness in parts and twisting nature of the road. The almost level Monsal Trail is ridden by leisure cyclists of all ages requiring no gears with cycles available for hire at Hassop station and Blackwell Mill.