Union Pacific SD45 #46, UP GP30-B #717B, UP DD35-B #86B and an SD40 #3097 at Las Vegas, Nevada October 06, 1979. Photo taken from my slide collection, no photographer listed on slide.
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.