One of the finest displays of raw power was the movement of iron ore trains over the Alleghenies. Upon the arrival of a ship at an eastern pier such as Greenwich in South Philadelphia (or Baltimore and Morrisville), these trains would move the heavy contents inland to Pittsburgh area mills in fleets of approximately 100 cars. So dense was the lading that PRR built an extensive fleet of G-38 and G-39 ore jennies that found their way well into the Conrail years. It is a late summer afternoon at MG interlocking, high on the Allegheny slope, as four haulers are wide open with their 102 car train. In just moments the helpers will appear around the curve.
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.