The sunset is close to being over and the blue hour begins. In this 30 second exposure four cab units displayed, BN 1 F9A, C&NW 411 F7A, MILW 118-C F7A, and MILW 37-A E9A.
The very first SD type locomotive, built in May 1951 as General Motors Electro-Motive Division's prototype Demonstrator #990. The 1518 is viewed here in yard 2 at IRM.