A very clean BNSF 6310 leads a westbound coal load up the 2.2% east slope of Mullan Pass. The train is passing thru the rock cut on the approach to Austin Creek Viaduct. Mid-Train is manned 4 pack of MRL SD70ace locomotives, with one DPU pushing on the rear. Mullan Pass is the most challenging obstacle for trains westbound on the former Northern Pacific Mainline....