The GP40 is 3 feet (0.914 m) longer than its EMD 567D3A-engined predecessor, the GP35, and distinguished visually by its three 48-inch radiator fans at the rear of the long hood, while the GP35 has two large fans and a smaller one in between. It was built on a 55 ft (16.76 m) frame; the GP35 was built on a 52 ft (15.85 m) frame - as was the GP7, 9, 18, and 30. The difference in length can be seen in the GP40's ten handrail stanchions compared to the GP35's nine.[1]