This achievement will unlock when completing chapter seven of episode three.
*** Spoiler - click to reveal ***Retrieve the blowtorch from the station, use the duct tape found in the FDA truck, uncouple the tanker, as soon as Ben spots the oncoming horde, the achievement will unlock.
A lot of achievements are quite glitchy in this game, if an achievement doesn't unlock right away then just continue playing and the achievement should pop shortly after.