High Quality Content by WIKIPEDIA articles! NSB Di 3 is a class of 35 diesel-electric locomotives built by Nydqvist och Holm (NOHAB) for the Norwegian State Railways (NSB). The class was built between 1954 and 1969, and delivered in two series, Di 3a and Di 3b. They are based on the Electro-Motive Division F7 and are equipped with EMD 567 engines. They have a distinct bulldog nose and were numbered 602–633 (a-series) and 641–643 (b-series). The locomotives had a prime mover that gives a power output of 1,305 kilowatts (1,750 hp). The a-series has a Co`Co` wheel arrangement, while the b-series has (A1A)`(A1A)`. The b-series has higher top speed, but lower tractive effort.