Three MPI MK5000Cs and a single SD40 lead a Utah Railway coal train through Spring Canyon on January 6, 2001. Beginning late in Oct. 2000, the Utah Railway began testing three MK5000C locomotives, deciding to purchase the entire production fleet of six units by November. In April 2001, the MPEX 9901 and 9902 would become the Utah Railway 5004 and 5005 with the SP 503 becoming the 5003. Unfortunately, the MK5000Cs were prone to main bearing failure on both the CAT 3612 diesel engine and the Kato alternator. MPI in Boise replaced these components with standard 3500 HP EMD SD50 prime movers, alternators, and even second hand car bodies by 2003. All six of the original MK50-3s continue to serve on the Utah Railway, hauling coal and local freight traffic for BNSF in the Beehive State.