Montana Limestone Company’s colorful EMD SD50Fs Nos. 5404 and 5438 rest at Warren, Montana, on June 24, 2016. These two former Canadian National locomotives operate at a dedicated truck dump and rail load out facility along the BNSF’s Casper Subdivision, where they operate up and down a 1.5-percent grade on a new rail spur hauling limestone. Total length of MLC trackage is about 18,000 feet, and the locomotives are not used on BNSF trackage. This chemical-grade limestone is quarried nearby, and MLC supplies limestone to the scrubbers at Basin Electric’s Leland Olds Station near Stanton, North Dakota. Trains bound for Leyland Olds Station are almost 100 cars long and heavy, necessitating the big six-axle cowls. This pair, along with four Dakota, Missouri Valley and Western units, are the last operating SD50Fs in existence.