Yes.Wasting ATACMS on the Crimea bridge is idiotic, im sure there are tons of better targets ATM.
Crimea bridge would be done if Ukraine manages to get to the Sea of Azov anyway.
Because this bridge is very solid and there more power is needed to damage this seriously....to waste anything just in order to make 1-2 weeks for repair is useless.
I can't tell about railroad, maybe they might use some kind of sabotage etc? Without missiles used. While I had sold stuff like panels etc for bridges but not for railroad companies, for these just cement etc stuff. They does have their own specialists and I don't have qualification to discuss in depth about railroad stuff.