I haven't got trains working properly in Normandy in the ME either.
Do you have civ traffic turned on in your settings?
If you turn them on, either in your settings on in the settings for the mission, trains drive around the tracks but it's less than ideal because I don't think a kill counts for anything and sometimes they drive through each other.
Idk if this is still the case, but if you haven't set the year to 1944 I think modern trains used to drive around instead of steam trains.
Hope this can help you out til someone who's more of an expert with the ME can!