For a time in the late 1990's, UP ran 5-packs of SD40-2R's on high priority trains. On the point of this consist is UP3101 which was just released from the paint shop a few weeks before. This unit was previously UP1996, painted in a commemorative scheme for the Atlanta Summer Olympic Games, and along with UP1896, carried the special paint scheme for less than a year. UP3101's original number was UP3399.
The EMD SD (special duty) series are a strong and reliable kind of locomotive which still serve America's rails today. They have proved themselves reliable by clocking in several million miles of freight service over several decades.