originally, as a noun, “le train” comes from the latin word trahere “to pull”. It’s then use to describe a convoy of animals. Later its meaning evolved into the “the going motion” (of a horse, a human).
It’s currently in that sense in “arrière-train” to designate the back legs of a quadruped. “Aller de bon train” = to walk briskly, or in automotive, the “train avant” and “train arrière” are the front and rear axles.
There are other expressions like “le train-train quotidien”, meaning the daily grind.
originally, as a noun, “le train” comes from the latin word trahere “to pull”. It’s then use to describe a convoy of animals. Later its meaning evolved into the “the going motion” (of a horse, a human).
It’s currently in that sense in “arrière-train” to designate the back legs of a quadruped. “Aller de bon train” = to walk briskly, or in automotive, the “train avant” and “train arrière” are the front and rear axles.
There are other expressions like “le train-train quotidien”, meaning the daily grind.
edit: additional information to the etymology