My favorite French train was the orange and silver gas turbine trainsets (RTG) the SNCF used in non-electrified express lines. They are retired and scrapped, but at least one power car is preserved at a French train museum.
I thought I read that Iranian railways bought some used trainsets after SNCF was done with them (circa 2000), but I have not found the photo evidence of that. Makes me wonder if rail photography of trains in Iran is verboten and punishable by public stoning or something.
Pages of cool SNCF turbotrain thumbs: [trainspirit.fr