Don't Go Back

Don't Go Back is the fourteenth episode of the twelfth season.

Plot
Bill and Ben are to load and shunt trucks of stone for Henry, but they get sidetracked declare a backwards race to prove it. Unfortunately, the three heats (which end in a draw) cause Edward, James, Donald and Douglas to be derailed after Bill and Ben collide with them. When Henry arrives, none of the trucks have been loaded. While arranges the train and collects Rocky to put Edward, James, Donald and Douglas back on the rails, Diesel clears away the mess from the races. When the two are done, Diesel challenges Thomas to another race, which Thomas orders to be forward. This time, both arrive at the quarry gates at the same time.