 Reliability was not as high as anticipated; the twenty-cylinder prime mover was prone to crankshaft failure from engine block flex.Though it produced more than the 16-645E3 in the SD40, some railroads felt the extra horsepower wasn't worth it, even after EMD strengthened the block to eliminate crankshaft failures.At low speeds, when tractive effort was adhesion-limited, the SD45 provided no advantage over the SD40.