With a 54-inch-wide padfoot drum, the AC 40 P4B delivers 19,110 pounds of compactive force from its 7,500-pound chassis. Dual drive motors at the rear are equipped with a flow divider to deliver excellent traction without an axle, Ammann says. The hydrostatic braking, drive, and vibratory systems are powered by individual pumps. It has a 41.5-hp four-cylinder Kubota diesel engine. An optional smooth drum shell kit can be bolted on for added versatility.