I've resisted this thread so far because I've posted on this subject once or twice before.
However, one of the routes I sometimes mention that ought to be reopened is Chinley - Matlock. This would allow:
Better local access to Buxton, Matlock, Bakewell and the Peak District national park.
A more direct inter-regional service between the North West and East Midlands, allowing Hope Valley capacity to be used for North West - Yorkshire flows.
An alternative route for peak district mineral freight.
An alternative Manchester - London Route.
On previous threads, posters (who shall remain nameless) suggested that Project Rio loadings were scarce and therefore suggested limited demand for NW - East Midlands passenger flows. This does suggest a certain level of surpressed inter-regional demand.
Thisis in addition to the 2008 study which looked at local traffic alone and found that some configurations of reinstatement could be justified on that.
However, I note that in January's "Modern Railways" it states that during Project Rio, the service received "good support from East Midlands Passengers and ticket sales from Leicester to Manchester doubled".