It bothers me already that the trigger buttons aren’t used to make the wagons go forward and backward. Why can’t they just have the same controls as cars?!
Anyway, how are you meant to reverse them? I had to restart a mission after crashing into some trees and couldn’t get back out. Surely there’s a way to go backwards?
Should be R1 or RB to make a cart or wagon go backwards. Same button that you use to brake or slow the wagon down. Once you are stopped, press the button again and you will reverse.