Known for their versatility, the GP series was designed to handle any sort of assignment. The "Torpedo Geeps" - so named for the roof-mounted air tanks - were adapted for passenger service. With air tanks moved to the roof, there was room for a larger water tank below the frame. Most roads selected this option so that locomotives could spend weekdays hauling commuters and then keep busy on freight runs over the weekends or third shift. Some opted to move the air tanks for the benefit of larger fuel tanks. Just like the prototype, these locomotives will look right at home on freight or passenger trains on your layout!