Oh I agree. “Old hat” was a deliberately flippant term. Nevertheless, the decision to go for 25Kv only a year or so after MSW was completed didn’t exactly enhance the prospects of its electrification being extended.
I thought the original intention was to wire through the original tunnels, and it was only once work was well underway that it was decided to replace them, thus further adding to the delay in completion.
The point is was trying to make was that had the initial project been completed in the expected time frame (1944?) the impetus to extend it eastwards and westwards may well have been there. All the delays (the biggest one: the war, not being the railway’s fault) led to that impetus being lost.
The MSW (Woodhead) scheme was finally completed in 1954 and the decision that all future overhead electrification would be at 25kv AC was made in 1955, I think, so one year is correct. That said, there is nothing to say that there couldn't have been logical extensions made to the orginal scheme at 1500v DC.
The line's electrical control centre at Penistone had space for more panels to take into account for this. Retford is one that is rumoured and there was certainly talk of extending the scheme west into the 1960s.
As
Taunton says, there should have been no reason (other than BR's own questionable policy) why 1500v DC couldn't have lived on beside the new AC lines. (Japan is another country where this still happens today) and it is true that the Class 76 was a very robust design and one of the most reliable on BR. Certainly a bit better than the dear old Class 84!
If perhaps there had been just a bit more DC done before 1955, it could have happened. Obviously there are now dual voltage locomotives in Japan, France and elsewhere so it is not even that much of an issue as it once might have been.
I am planning a walk from Manchester (Broadbottom / Hadfield) to Sheffield and then Wath to Penistone in June over as much as the line / close to it - as possible. The first time I have been back since photographing it and travelling on it as a teenager in 1979, so I am doing a bit of research for my blog at the moment.
I found this from the glossop heritage society very useful - it quotes local newspapers of the time and contains some details I have not seen elsewhere.
https://glossopheritage.co.uk/ghtarchive/railways5/
There is a quote from an article in April 38 saying the scheme could be finished in 2.5 years - so 1941/42 is one possible date. It also supports the theory that the plan was to wire through the original tunnels.
The usual explanation is that a thorough inspection after the war revealed it to be impossible to proceed through the old bores. Although there is always the question of extra intensive use during the conflict, one wonders whether they might have still discovered the same thing in 1940?
The delay was about 10-13 years, 6 or 7 of that for the war and the rest for a new tunnel.
But, yes, without the war (with or without the new tunnel) there probably would have been a bit more of a 1500v DC network and that might have passed a critical mass test for retention as in France, Japan and elsewhere.