On a beautiful afternoon in May of 1999, a westbound UP pig train crosses the Willcox Playa with two SP units for power. At the time this photo was taken, there was only a single track across this mysterious dry lake, but now there are two.
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.