Sebastien-
My ex-wife was from Charleville- Mezieres. Her father was chief engineer for Les Hautes Fourneaux de La Chere (sp?), a steel company there. In the early '70's he gave me a tour of the plant (ancient, and now closed). They had stored inside a locomotive that we might call a "grasshopper". The B&O museum has a similar one. It must have dated from the early 1850's, or even earlier, I'm guessing? I think it was standard gauge. Wonder if it's still there?
I looked at the two websites you attached. Fantastic and very nice work.
Merci beaucoup.
Ned