 The GP40 is 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 frame; the GP35 was built on a 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.