Found that Railway tracks and Rivers that get laid down on Rock Texture will break up and will cause weird things with the trains or barges that travel on them.
It's seems to be ok if the Rail or River make a 90* turn on a Rock tile but not on a straight away.
Don't know if this a bug and is going to be fixed, just letting you know.
Rail running East to West

Rail running North to South

River running East to West

River running North to South

Pokie