On the morning of June 30, 2021, a westbound BNSF freight climbs the 2.2 percent grade up toward Mullan Pass at Austin, Montana. The head end is one curve away from the big horseshoe curve through Iron Ridge cut. In the background is a Montana Rail Link manned helper set of four EMD SD70ACes, cut into the train about two-thirds from the rear, adding their 17,200 horsepower of tractive effort to getting the train over the pass.