Deutsche Reichsbahn introduced its DRG Class SVT 877 Hamburg Flyer in 1931.

It served as inspiration for other countries to manufacture similar diesel multiple units for express trains.

[1] Happy with the trials, NSB signed an agreement with Strømmens Værksted to manufacture four three-car units with a similar design.

There are unconfirmed claims that two partially completed trains were stored in the closed-off tunnel at Bøn for the duration of the war, to avoid German forces from accessing them.

[1] Trial revenue services commenced in February 1946 on the Bergen Line from Oslo to Geilo.

By then the roller bearings in the prime mover's big ends were sufficiently weakened that they were causing engines to malfunction.

Low standards caused by wartime manufacturing combined with dust and rust in the engines through four years of storage required a major clean-up of the prime movers before they could be returned to service.

The prime movers were manufactured in 1939 and their big ends had to be replaced with sleeve bearings to improve reliability.

The trains were pulled for service in January 1950, this time because of defect bearings in the power transmission.

While the trains were placed on hold, NSB attempted to install new Paxman prime movers.

These were less powerful, rated at 375 kilowatts (503 hp), and instead renovated Maybach engines were installed.

They proved popular with the public, allowing for faster travel times from the capital to Norway's second and third largest cities.

NSB therefore decided in 1956 to order two more units, allowing for daily services also on the Bergen Line.

NSB initially intended to order the new units with reversible seating and the kitchen in the center car, but chose to retain the former layout in able to retain a universally interchangeable fleet to avoid complicating the booking process.

However, the new units were delivered with doors on both sides of the train, compensated through and overall longer length and a tighter seat pitch.

[3] Unit 88.04 experienced a brake failure and was parked at Bryn Station to be shunted to Loenga.

The units remained unstable and frequently broke down during operations and were in a steady need for maintenance.

The motors weighed 2,800 kilograms (6,200 lb) and powered each their Voith three-stage hydraulic gear shift.