Montana Rail Link's Mullan Pass is the crossing of the Rocky Mountains in Southern Montana on the old Northern Pacific route. This short section of railroad has two horseshoe curves, two spectacular trestles and Mullan Tunnel. MRL uses older, rebuilt power, SD4O's, SD45's, SD45-2's SD19's, GP9's, some in MRL's dark blue and some still in the original RR's colors, while BNSF uses anything they own. Taped in fall, 1997.