Over the annals of time, I have lost the detail

of where this picture was taken. All I can say was that it was on a non-electrified mainline between Ancenis and Nantes. It shows a pair of SNCF's class X4500 units. These units, constructed between 1963 and 1970, were known colloquially as 'Caravelles' by railwaymen due to them sounding similar to the airliner of the same name! All were withdrawn by 1990 but a few examples live on after being sold to Romanian railways.