SLSF 4503 at BLWorks in Philadelphia with Frisco and Baldwin crews in front. The 4503, a coal burning FFF freight engine, was the first 4500 on Frisco property. With driver diameter of 74 inches and weight of 474,520 pounds this was truly a huge machine. According to Collias "Frisco Power" pound for pound the 4500s developed more horsepower than any other 4-8-4. Twelve of these machines were delivered in August of 1942 and they were immediately assigned to handle the unprecedented war time traffic on the Eastern Division. Information and Photo courtesy of John P. Mann.