SNCF This turbotrain RTG  - first engine is Nr 2040 - is probably bound from Boulogne-Aéroglisseurs (Hoverspeed) for Paris.
It is passing now the viaduct "La Reine Blanche" in the woods of Chantilly. 
The new viaduct is being built in the background
1981. Forêt de Chantilly - Photo JP HAMEAU prepared by Patrick Meunier Pmeunier23@aol.com www.pixyrail.com