Cylinder and driving wheel dimensions were unchanged. Locomotive brakes employ large shoes which press against the driving wheel treads. In the main, numbers were allocated in descending order of driving wheel diameter. The engine was liquid-cooled, with a radiator over the rear driving wheel. The outside frames were curved over each driving wheel axle. The album also contained his most widely covered song, "Driving Wheel". Most subsequent versions of "Driving Wheel" show Parker's influence, including the distinctive bass line. The hot driving wheel axleboxes were caused by the main frames being out of alignment.