Mr. Pettigrew (The Nemesis Series)

Nearly starved, missing half a leg, Beau Boone stumbles out of a cattle car into the hell on wheels Transcontinental Railroad town of Nemesis, and into gunsmoke and battle to rival that of the war he's just escaped. Mr. Pettigrew and Miss Alice, of the Angel Cloud Saloon, befriend him, and soon he's sitting shotgun in the middle of a smaller, but equally deadly, conflict. And it's a war no one can win.