The locomotives are equipped with a Caterpillar 3516 DI-TA prime mover, which provides a power output of 1,570 kilowatts (2,110 hp) and a starting tractive effort of 270 kilonewtons (61,000 lbf).

Twenty locomotives were delivered in 1996, largely based on MaK's previous production series, the Dutch NS Class 6400 and German DE 1002, although receiving some upgrades to the specifications.

[3] Originally there were plans to order additional Di 4 units, but this was discarded and instead a new class was pursued,[4] as NSB wanted similar, but slightly more modern, locomotives.

[5] On 23 November 1992, NSB's board decided to order ten similar units, later expanded to twelve, which would primarily be used in passenger trains.

Unlike their larger counterparts, which were unsuitable for service and returned to the manufacturer, the Di 8 proved a sufficiently reliable to remain in operation.

On the other hand, the locomotives had high operating costs, in part because of the twin configuration, and proved less reliable than NSB had hoped.

[10] NSB's initial motivation for the smaller units was to haul conventional local freight trains and affiliated heavy-duty shunting.

With the reorganization of the railways during the late 1990s and early 2000s, this job fell out of use, making the locomotives poorly suited for NSB's network.

The locomotives passed to CargoNet in 2002, after the split of Norwegian State Railways (NSB) into passenger and freight companies.

[9] On 4 April 2011, a fire broke out on a Di 8 locomotive at Kløfta on the Trunk Line while hauling a 16-wagon train of jet fuel to Oslo Airport, Gardermoen.

[11] In October 2011, GB Railfreight was awarded the contract for the operation of the railway after Sahaviriya Steel Industries had bought and reopened Teesside Steelworks in Redcar, United Kingdom.

[13][14] They were thus in need for locomotives to haul the internal torpedo trains with liquid steel between the steelwork's blast furnaces and continuous casters.

This provides a power output of 1,570 kilowatts (2,110 hp) at 1,800 revolutions per minute, allowing for a maximum operating speed of 120 kilometers per hour (75 mph).

It takes advantage of water-cooled gate turn-off thyristor (GTO) semiconductor technology for pulse-width modulation inverters to supply power to the alternating current traction motors, located on a nose-suspended drive.