There were also two single bore tunnels (Kelmarsh and Oxendon) which had very limited clearance, meaning that passenger stock in regular use in that era would have required bars on the droplights. Any attempts to increase the gauge for containers or electrification would have been very expensive. There were also numerous level crossings, at least two over 'A' roads which would have required bridges building. Although none of the issues were technically insurmountable, the total cost of them all was probably prohibitive.
Yes, thanks for the details. I never travelled over the line, just knew it was not suitable for development without a lot of money.
Reverting to topic more directly, all this talk of loss of passenger traffic when the core part of the closed GC at places like Brackley and Lutterworth, and Leicester to Rugby (at the time and in the future) is understandable, but it ignores surely the biggest loss caused by the closure, namely the truncation of any sensible route north by rail from Aylesbury and locations immediately south thereof in the northern Chilterns on the former Met route.
Granted, these places were much smaller then than today, and travel by the general public was much less prolific, but a simple two-car DMU shuttle running Aylesbury – Bletchley (or even Northampton) could have been introduced with minimal or even no new infrastructure cost and surely have produced far more passenger journeys than any new chords at sth Leicester, Rugby or Loughborough. That, I would posit, would have been far more practical as a rail service even at the time, and certainly into the future to today as the populations and importance of Milton Keynes increased.