Conceived in 1931, the Pennsy’s P5a was intended to be the last step in the search for a mainline “juice jack” that had begun with the FF1 in 1917. A collaboration between General Electric, Westinghouse, and the Pennsy’s electrical staff, the design proved to be a winner. Engine crews liked the P5a’s because they were smooth, powerful, and cleaner than the K4s Pacifics they displaced on many runs. Six 625 hp electric motors geared to three axles with 72-inch drivers gave the new engine 3,750 continuous horsepower and a top speed of 90 mph on passenger runs.

But the success of the Pennsy’s passenger service proved too much for the P5a, whose limit was about 8-10 cars on high-speed runs. The introduction of the GG1 in 1934 allowed the Pennsy to operate longer passenger trains with a single locomotive, and pushed the P5a into freight service – where it found its true calling. Regeared to a top speed of 70 mph, the P5a fleet became the backbone of electric freight service on the Pennsy for the next several decades.

The P5a’s were originally built with box cabs and, like all box cab locomotives, made engine crews a bit nervous about their exposure in an accident. After a grade crossing collision with a truckload of apples proved fatal for the crew, the final 28 P5a’s built in 1934 and 1935 were redesigned with a center cab in the image of the GG1, which was then in production. With their riveted bodies, these P5a Modifieds, as they were called, bore a strong resemblance to the original GG1, “Old Rivets.”

The P5a Modified returns to the Premier Line roster in 2020 after a fourteen year absence, decorated in four authentic paint schemes and outfitted with our smooth operating automatic pantographs.

Did you know?

The prototype P5a, like our model, featured a blind (unflanged) center axle to allow it to negotiate tighter curves.