The railroad is about 60 miles south of the town of Lyon. The starting point "Tournon sur Rhône" is on the right bank of the river Rhône. The railroad follows the river called "Doux".
An interesting feature is that it shares the first mile of track with the standard gauge SNCF line on "classical" 3 rail track. The railroad used to be part of a large ng network with a total length of more than 100 miles which was closed down 1968.
For more information see link below (english version by clicking on the british (!) flag...