Getting a spin At the Union Pacific’s South Morrill Locomotive Facility in Nebraska on September 14, 2017, a General Electric 16-cylinder 7FDL16 from Union Pacific AC4400CW 6704 gets a spin 180 degrees while hovering over the shop floor. The old prime mover will be placed next to the new one so the crew can remove the old generator, since it is still in “good order,” and it will then be mated with the new prime mover before installing it back into the locomotive.