While the engineer remains at the throttle of Rio Grande 5401 East, two other crewmen inspect the power. The manifest has just passed the west end of Gilluly, where curvature and a steep grade put mountains of stress on the locomotives.
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.