The longer the train, the more these curves get accentuated. This ISCLB was a good 10k+ feet, and with a good TOB ratio, is making a quicker descent of Cima Hill than your ordinary freight.
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.
