 The locomotives were the result of a contract won by MaK and Brown, Boveri & Cie to replace Nederlandse Spoorwegen's old medium power locomotives.The design is based upon the MaK DE 1002 with modifications; the locomotives are longer to incorporate additional equipment, in particular an auxiliary diesel generator, as well as ATB equipment; the bogies are longer than on the DE 1002 to incorporate tread brakes instead of disc brakes.For Nederlandse Spoorwegen 120 of these locomotives were built, numbered 6401-6520.