The traction system of the El 17 was based on the DB Class 120 of Germany (BBC, AEG and Siemens) and were among the first in the world to feature three-phase asynchronous motors.

The units were ordered to be used on the intercity Bergen, Dovre and Sørland Lines, but were plagued with technical faults (overheating traction equipment, transient voltages, etc.).

The unreliability and lack of sufficient power forced NSB to instead use them in the regional Vestfold and Gjøvik Lines.

At first electric multiple units were considered, but NSB instead chose to order locomotives and waggons, to have greater operational flexibility.

The two were planned to have the same rectifiers and motors, but due to weight restrictions the El 17 received the same type as Class 120.

At the same time, the delivery of the B7 passenger cars from Strømmens Verksted was made, and the first train with an El 17 and B7s in regular service operated on the Dovre Line on 14 September 1982.

[2] Eventually NSB felt confident that they had found a technical solution that would be satisfactory, and ordered another six units to allow all trains on the Dovre, Bergen and Sørland Lines to be hauled with the class.

The locomotives have three-phase asynchronous motors with a continuous output power of 3,000 kilowatts (4,000 hp), allowing a maximum speed of 150 kilometres per hour (93 mph).

The units receive 15 kV  16.7 Hz AC power from a pantograph and are the first class of locomotive for NSB that has regenerative brakes.

Each locomotive is equipped with four NEBB BQg 3855 motors, giving a Bo'Bo' wheel arrangement and a maximum tractive effort of 240 kilonewtons (54,000 lbf) on dry rails.