The invention relates to a diesel locomotive, in particular to a novel meter-gauge AC transmission diesel locomotive. The diesel locomotive includes air conditioner, auxiliary transformer cabinet, radiator, expansion water tank, car body ventilator, diesel engine, muffler, air filter, main generator, resistance brake device, brake valve installation cabinet, electrical cabinet, Seats, consoles, main converter cabinets, cooling towers, sand boxes, fire extinguishers, fuel tanks, batteries, main air cylinders, ECM control boxes, bogies, couplers, obstacle removers, driver's cab 2, auxiliary rooms, cooling rooms , power room, motor room, electrical room, driver's cab and frame, the diesel locomotive has advanced technology, compact and reasonable structure, convenient and quick assembly, reliable connection, suitable for meter-gauge lines, and can adapt to various harsh weather environments. At the same time, the amount of daily maintenance is relatively small, and it is easy to use and promote.