D&RGW PA-1 #6011, Salida, CO, August 25, 1965, Photo by Chuck Zeiler

The PA-1 was powered by a model 244 diesel coupled to a GT566C1 main generator driving four GE 726 traction motors. It had a 1200 gallon fuel tank, carried 1000 gallons of water (the water tanks were inside the carbody), weighed 303,000 pounds, and produced a continuous tractive effort of 30,500 pounds at 20 mph. This unit was delivered as #601 (c/n 74686), built April 1947, retired December 20, 1967.

The train is the Royal Gorge. Although the PA's were considered better that EMD E units for mountain passenger assignments, the Rio Grande ultimately decided on a four unit set of EMD F units for the California Zephyr assignment. A three unit set of PA's would deliver the same gross horsepower as a four unit set of F's, but the EMD's could deliver 20,000 pounds greater continuous tractive effort, and had the additional reliability advantage of one more power plant and four more traction motors.