[rplst8]

Most rail equipment, powered units included, can be pulled along by just about any other powered railcar.

[euroderf]

I wonder if there might be a bit of switching choreography required, if a unit in the middle of a train dies. And what if an axle jumps the rails ? What does rerailing look like ?

I know these are all solved issues for railroads, but I wonder if tunnels and lack of lateral access by heavy equipment makes a difference.