Bridge infills by National Highways authority. More sabotage of potential cycle routes.https://www.theguardian.com/uk-news/2022/dec/19/national-highways-told-it-must-reverse-burial-of-victorian-railway-bridge

Presumably because "our job is management, development and maintenance of the strategic road network" (plus signage and standards).

Apparently they took over the Historical Railways Estate just under 10 years back as this was moved around between companies.  They are now "responsible for looking after it".

Does anyone know what the story is?

Did someone do a quick evaluation and say something like the following: "right - these aren't needed for new A-roads or motorways.  They're still costing us cash though.  Also some might fall on people / disrupt roads.   We need to avoid these liabilites.  We've managed to get some money to sort this - so if we can't knock 'em down just fill 'em in".

I would speculate "strategic" and "cycling" / "active travel" are utterly unrelated in the thinking of the people who make these decisions.  Since they're "roads" presumably it's not their business to consider if we might need these again - sooner - for some kind of ... train.  If we cut down on our road use?

Local authorities sometimes have a broader understanding.  Although not always in a "cycling-friendly" way.  Edinburgh has installed a new generation of signs and signboards * on some of its former railway lines (now paths).  Some of these suggest that one day these will be converted back into e.g. tram lines because this is "clean" and "reliable" transport.  Sorry mate - we still can't see the cyclists (or even walkers)!

* This is of course useful, but I wonder just how much has been spent on signs now and whether over the last few years that's a cycle-path's-worth of cash?  Very rare that signs are controversial of course, and they don't reduce space for drivers.  But you can proudly announce the money you've spent on active travel!