Trains operate in and out of Anaheim, California, primarily on weekdays. As a result, a trio of Union Pacific 3GS21B GenSets wait in the small facility for the call to duty the next day - Monday. These three units - UPY 2723, 2724 and 2719 - were built by National Railway Equipment in 2007. (The purple sign with the "D" on it indicates a derail, and as long as the "D" is visible to the engine crew, the derail in lined to knock any runaway equipment off the rails.)