New Zealand DX class locomotive.

The New Zealand DX class locomotive is a class of 49 Co-Co diesel-electric locomotives that currently operates on New Zealand's national railway network.

Built by General Electric in Erie, Pennsylvania, United States,they were introduced to New Zealand between 1972 and 1976.

The DX class is still used primarily on heavy freight trains. The majority of the class now operate in the South Island, predominantly hauling coal trains between the West Coast mines and the port of Lyttelton near Christchurch. The trains consist of up to 30 CE class hopper wagons each holding 52 tonnes of coal, and require five members of the class to haul the train up the 3% (1 in 33) west-east grade of the Otira Tunnel, and two members to haul it on the other sections of the line. These services are now exclusively hauled by the DXC sub-class. The class are also involved in general freight operations, and also employed periodically to haul the TranzAlpine and Coastal Pacific passenger trains.