The New Zealand DX class locomotive is a type of 49 Co-Co diesel-electric locomotives that currently operate on New Zealand's national railway network. All locomotives are owned by KiwiRail. Built by GE Transportation in Erie, Pennsylvania, United States, they were introduced to New Zealand between 1972 and 1976. The class is based on the General Electric U26C model, a narrow-gauge version of the GE U23C model. The locomotives are regarded as one of the most successful purchases in NZR's history.