Doing the Crater curl On the morning of July 31, 1996, a Southern Pacific coal train climbs through the Crater Loops at Crater, Colorado, on the former Rio Grande Craig Branch. Five General Electric AC4400CWs power the train, with two on the point, two mid-train, and one following up on the rear of the train. In this view, mid-train Nos. 332 and 256 are in the middle of the loops, while lone rear DPU No. 266 works below.