Many years ago, in BR days, I did a lot of surveys in East Anglia to replace ageing and failing telegraph pole routes with cables using the rail mounted mole plough owned by Cuthbertsons from Biggar in Scotland. A lot of them happened and are still in use today, some now at least 48 years old! One I did was March to Spalding. When I told my boss how much it was likely to cost he told me not to do anything more with it as the cost would close the line. The line was basically a freight line for, mostly, coal traffic to London which went via Cambridge but this was reducing at quite a rate so the passenger service couldn’t support the line on its own.