I noticed that when I was placing POI's the was one for a railroad crossing and none of the calls we have now happen at a railroad crossing, So I want to suggest some calls that could go with that POI. some of the calls could be:
car stuck on tracks, semi truck stuck on the tracks(possibility of dangerous materials),Car/truck hit by train with or without injures, pedestrian hit by train, etc
Edit:
With the calls of a vehicle stuck on the tracks there could be a 50% chance that the fire department or police can't get the vehicle off the tracks in time and a train hits it and more units are needed to respond to help with injuries, maybe a fire breaks out and another fire truck is needed,etc