The Komatsu D575A is a tractor crawler produced in a 'SR' or Super Ripper bulldozer/ripper configuration, or as a dedicated bulldozer in the form of the 'SD' or Super Dozer. Both models can move of material per pass using the standard blade. The D575A-3 SD Super Dozer can move of material per pass if equipped with an optional blade. The D575A-3 can dig to a maximum depth of using its single-shank ripper. Commonly referred to as the 'world's largest production bulldozer', the D575A series bulldozers were produced by Komatsu Ltd. in Osaka, Japan. Surface mine operators in the United States, Australia and Japan were the primary users of the D575A, although they were sometimes used in heavy construction applications and quarries as well. Development Komatsu first showed a bulldozer prototype, the D555A, to the public at the Conexpo equipment exhibition in Houston, Texas in 1981. Due to economic conditions at the time, development was stalled for much of the 1980s. A successor to the D555A prototype, the D575A-2 SR Super Ripper, began field testing in North America in 1989 by the Cooney Brothers Coal Company in PA where over 1000 hours were logged. Prototype machines are also believed to have been tested at the Harrison Coal and Reclamation Park. Full production began in 1991. The first production machine, delivered in 1992, was initially trialed in PA where the prototypes tested. The first machine was built up by Anderson Equipment Company and then sold to American Asphalt and Paving Company where it initially worked in Las Vegas. The D575A-2 SR Super Ripper was joined by the D575A-2 SD Super Dozer in 1995. The first D575A-2 SD Super Dozer was purchased and placed into service by the Princess Beverly Coal Co. in Cabin Creek, West Virginia. The updated models, the D575A-3 and D575A-3SD Super Dozer were introduced in 2001. Series The first series of D575A bulldozers were the D575A-2 machines. These were produced in both SR 'Super Ripper and SD 'Super Dozer' configurations. These models were produced between the years of 1991 and 2000 and 41 machines were built. In 2001 the D575A-3 machines were introduced. These were produced in both SR 'Super Ripper and SD 'Super Dozer' configurations. They wore a new trade dress however most of the upgrades were electronic. Upgrades included features such as the 'Palm Command Control System', smooth and soft operation modes, ECMV controlled transmission, ECMV controlled