I'm remembering the work of Bicycle Bob Silvermann from le Monde a Biciclette in Montreal - when faced with the challenge of access to bridges across the St Lawrence River
Perhaps a small team of 'bunnies' might turn up to use the Schroedingers Bridge under the railway, that Defra says exists but real life suggests otherwise?
Rabbits are notoriously good at burrowing, so if that bridge is still there, it just needs digging out?
As with Doubledykes Road this project will be at GRIP stage 7 or 8 and making changes has penalties & is highly discouraged
BUT if the bridge abutments remain, and a basic 4 metre Armco tube can be dropped in to place, with spoil from the digging out then used to cover it over, this might just be workable, especially if a long blockade is scheduled to relay rails, or run out the knitting...
Again if there is an opportunity to sit with the project team and ask the questions...?
I had some pricing for just such a tube from John Grimshaw recently as it would also have sorted a problem out at Preston - relatively low cost to deliver to site and assemble, then drag in to the gap between the old bridge abutments (which are presumably buried in the embankment)
web trawlers - any old pictures of this bridge?