The New Zealand TR class locomotive is a type of diesel shunting locomotives built by many different manufacturers. Defined as "shunting tractors" or "rail tractors" by KiwiRail and its predecessors, they are classified "TR" for tractor as a result. Many of these locomotives have been withdrawn, but some are still in service. The first locomotive of this class was built by NZR in 1924. The most powerful were Japanese-built Hitachi TRs, with 138 kW Cummins engines.