My wife and I a trip cross the pond in 2018 and I really wish I could have seen more trains like that. Other than riding the tube in London, the Eurostar from St Pancras to Paris Nord, and the SNCF from Paris to Bayeux and back, I didn't get to rid any other trains (and oddly didn't see many others running). We stopped in several coastal towns in the northern Med, but didn't see any trains moving around. I saw what looked at a distance like a line blasted out of the rock wall near Marseilles, but didn't see any trains on it.