List of Hotels, B&B's, Airbnb's, Etc. Next to or Overlooking Rail Lines - Trains Magazine

Check the railfan magazines - I know I've seen ads in them for such accomodations.

Establishments that may otherwise be in prime locations for railfanning may not want to tout that, as the general public may be less that enthusiastic about trains passing while they try to sleep.

I stayed in a place on my way from Deshler to Rochelle, on Carl's suggestion.  It was located adjacent to the tracks, but the staff wouldn't give me a "room with a view."