Trains between Ogden, UT and Evanston, WY typically run directionally (there is no 'left' or 'right' track because they crossover at Curvo further up the line) unless needed to diverge otherwise. In this case due to MOW work, a westbound train is operating on the track typically used for eastbounds as one track has a steeper grade than the other, and as a result through Sheephead Tunnel.
