(I was driving to work from my former neighbours' place. 50km. Two hours. Engorgement? Tell me about it.)

Yes I drove through that mess for 20 years. The only railway line that would have helped, the Saint-Symphorien sur Coise line, no longer exists and only actually operated between world wars 1 and 2 (Chemin de fer de Rhône et Loire - 6 avril 1914 - 30 juin 1933), in pretty hair-raising conditions, and never made a profit. (though I sometimes used to drive down to the St Etienne-Lyon line).

The long-term advantage, as I see it, of the tram-train format in that particular region would be feeder tram lines from the various villages. This could happen fairly fast at limited cost, as far as I can see, if coexistence of trams and cars on existing roadways can be accepted. That will not be an obstacle if the mobility crisis gets bad enough, I am guessing.

_{It is rightly acknowledged that people of faith have no monopoly of virtue - Queen Elizabeth II}