And how about Castleford - York. All the infrastructure is there, just run some trains !
This is a good point.
On this particular route, there used to be regular services between Manchester Victoria and York; for about 4 months during the winter of 1966/7, I used the 10.15 off Victoria as far as Wakefield Kirkgate, and from memory it was always reasonably well loaded. I also remember going on that particular service on a summer Saturday through to York shortly after the Calder Valley sets were introduced, and it was chocker.
Investment in additional T&RS, some subsidy, and changes to stopping patterns has the potential to increase connectivity massively. Using the Mansfield/Sutton-in-Ashfield area as an example, the combined population of these adjoining towns is about 150,000, but it is only served by the Robin Hood line between Nottingham and Worksop. If the Worksop terminators were to be extended the short distance to Retford and additional ECML services were to stop there, two objectives would be achieved; firstly, rail connections to the north for the Mansfield/Sutton area would be significantly improved, and secondly, direct rail connections would be established between Retford and Nottingham. Then, again by using existing infrastructure, a limited stop service could be established between Nottingham and Sheffield via Mansfield; however, it has to be recognised that some upgrading of the Robin Hood line may be necessary to enable such a service to be accommodated and for an acceptable journey time to be achieved.
Restoration of services over the former LD&ECR line east from Shirebrook to Edwinstowe and Ollerton has been suggested; again, this would be
"easy" as the infrastructure is in place and could be achieved by extending the Mansfield Woodhouse terminators onwards. No doubt some signalling changes would be necessary and replacement stations built, but the overall cost should be quite low.
From a political point of view the above are no brainer; Edwinstowe and Ollerton are in Mark Spencer's constituency, Labour won Mansfield for the first time in 2017 and held it with an increased majority in December, and the Ashfield and Bassetlaw constituencies were won by the Conservatives from Labour at the last general election.
The former LD&ECR line is still in place through to High Marnham; just beyond it, Fledborough Viaduct over the Trent was rebuilt by BR in the 1960s, and the route onwards to Pyewipe Junction at Lincoln seems relatively free from incursions since closure. Although I can't recall seeing reinstatement of this route in any proposals, could it be done as part of a programme which restores passenger services not to just as far as Ollerton, but all the way through to Lincoln? Consequently, could this take freight traffic off the Nottingham - Lincoln line, thereby eliminating the need to construct a flyover over the ECML at Newark? Then, could a regional connector between Lincoln and Birmingham be introduced, going via Mansfield/Ashfield, through to the Erewash Valley then Ilkeston, Toton - if a HS2 hub station is built there - Derby, Burton-on-Trent, then perhaps to Birmingham via Lichfield?
Whilst an Ashington passenger train service restoration wouldn't give many - perhaps no - network benefits elsewhere, some others have the potential to improve train services in other places, although some further investment may be required. Taking Harrogate - Ripon - Northallerton, if that was to be associated with the restoration to use of the Geldard Road Viaduct and perhaps some more platforms on the Wellington station side of Leeds City, could the XC NE/SW service reverse at Leeds and then go north to Darlington via Harrogate and Ripon? This, in turn, would free up capacity out through Cross Gates and on the ECML in the York area, and it's reversal at Leeds on the north side of the station and the removal of trains in the Huddersfield - Leeds corridor from the Holbeck area would further ease congestion at Leeds City's west end.
From what I've seen of past proposals for re-openings, they have failed to consider potential network benefits beyond the line being considered, and have often viewed the route being considered purely from the point of view of restoring what existed/how a line was used at the time of closure; the Leicester - Burton line, for example, has been viewed as a local connector, with services being extended through to Derby (and Willington station was rebuilt as part of the original Ivanhoe line proposals). But there is also a connection at the Burton end towards Birmingham, so how would journey times between Leicester and Birmingham compare if a direct service was to be run that way? What relief could such a service bring to the A42/M42 corridor? I don't think it was ever considered. Likewise the work undertaken for Derbyshire County Council and others regarding Matlock - Buxton/Chinley; but to be fair, at that time the possibility of splitting the Norwich - Liverpool service at Nottingham wasn't on the horizon, but by looking at it now would it make sense if the proposed Norwich - Nottingham - Derby service was to be extended through the Peak District to Manchester and the Liverpool - Nottingham service to be re-routed via Mansfield, as suggested above?
Whilst a reopening like March - Wisbech sounds nice and easy, apart from benefits to Wisbech what would it really achieve? This is the conundrum, and it comes back to the structure of our railways. Without deeper involvement from the DfT or the establishment of something like the Strategic Rail Authority to consider re-openings in a wider sense and which enables all network benefits to be taken into account (such as those suggested for Leeds in parallel with a Harrogate - Ripon - Northallerton re-opening), there is a danger that money will be wasted on re-openings which provide good soundbites (as it was on the Sinfin branch in Derby).