Boardgamegeek https://boardgamegeek.com/boardgameexpansion/181158/colt-express-horses-stagecoach
English - Colt Express: Horses & Stagecoach, the first expansion for the 2015 Spiel des Jahres winner Colt Express, introduces a 3D stagecoach that rides alongside the train from the base game.
Official https://www.ludonaute.fr/portfolio/chevaux-diligence/
French - Voici la première extension de Colt Express, Chevaux & Diligence.
Ludovox http://ludovox.fr/jeu-de-societe/colt-express-chevaux-et-diligence/
French - 1ere extension pour Colt express (As d'or, Spiel 2015)