I would say the rail bridge is firked, that amount of heat over a sustained period would expand the rebar cracking the concrete, they had an artic fire under a motorway bridge years ago up Nr where I come from and that is exactly what happened, they had to replace the spans. Plus the rails are probably softened and buckled.
Which bridge carrry’s the Crimean water supply, because if that’s out and they recapture the canal then Crimea has more woes.