Watch Hell on Wheels Season 4 Episode 13 Online right here via TV Fanatic. Cullen Bohannon quits his job on the railroad eager to search his family. But a case of smallpox in the Mormon fort pushes them onward. And yet an unlikely force might be able to help Cullen find his family, with a certain price. On top of that, Durant and the rest in Cheyenne prepare to move on towards the last leg of the railroad journey. It's a season finale worth watching.