The Dutch State Railways awarded a contract to Maschinenfabrik Kiel (MAK) to design an entirely new diesel locomotive in order to modernize the non-electric locomotive roster. The result was the diesel-electric class 6400, which was based on the DE 1002, a class used by several private railroads in Germany. Nevertheless, there are significant differences: For example, electrical components were used from the development of the class 120 electric locomotive. For the electronically controlled three-phase asynchronous motors to achieve the required power of almost 1,200 kilowatts / 1,608 horsepower, both the motor and the fuel tank had to be enlarged. This made the entire locomotive 1.5 meters / 4 feet 11-1/16 inches longer.
Most of the 120 locomotives of this type still have the classic gray-yellow NS paint scheme. However, since the freight service in the Netherlands had been privatized, a few locomotives have already been delivered in the new Railion red paint scheme.