"'We have had, of course,' said the young lady, who was rather
reserved and haughty, 'to leave the carriages and fourgon at
Martigny. And the impossibility of bringing anything that one
wants to this inaccessible place, and the necessity of leaving
every comfort behind, is not convenient.'"

Fourgon
(n.) An ammunition wagon.
(n.) A French baggage wagon.

So, such a wagon at the end of a wagon train would be a fourgon conclusion.