The flat-tread tires on the Volvo PT125R Pneumatic Tire Compactors exert kneading action and pressure to confine material between tires. The PT125R has pressurized water systems that include separate spray nozzles, cocoa mats and scraper brushes for each tire. The ballast compartments on the PT125R can be filled with water, steel, wet sand, or a combination of these materials and has a fully ballasted operating weight of 27,395 pounds (12426 kilograms). An 85-horsepower (63.4-kilowatt) diesel engine powers the PT125R compactor. Equipped with low- and high-speed ranges, the PT125R has a top speed of 15.5 miles per hour (25 kilometers per hour).