They had four motors providing a combined power output of 180 kilowatts (240 hp), allowing for a top speed of 60 kilometers per hour (37 mph).

These were built for use on the Lambertseter Line, but were found unsuitable for use on light rail service and later moved back to the streets.

More Gullfisk were considered, but their aluminum bodies were found to be unsuitable, they had issues with cracks in the bogies and their electrical system was prone to faults.

They were design with entrance through the middle door, which had during the high usage during the war proven to be inefficient and often led to two conductors being needed for each car.

[5] The second offer came from Strømmens Værksted and Norsk Elektrisk & Brown Boveri, for an enlarged model of the Class 1947 being built for the Bergen Tramway.

[6] Høka held the Norwegian rights to a Czechoslovakian patent for wooden-filled steel profiles that Hägglund used in its design.

The first tram arrived in Oslo on 1 September 1952 and, after final assembly and tests, entered revenue service on 11 November 1952.

[9] The original plan was to copy a concept from Stockholm, where the trams were run fast and frequently without trailers.

[9] Oslo Sporveier was not willing to pay the price for new trailers and therefore chose a combination whereby new bodies were built atop existing undercarriages.

This led them into the idea of converting older trams by keeping the most costly parts, such as motors and wheelsets.

The company approved that twenty units be built, stipulating that fifty would be converted should it prove successful.

They quickly received the nickname Chickens (Kylling), as a pun of being smaller than units built at Hønefoss (literally "Hen Falls").

[17] Although Oslo Sporveier was determined to buy bogie trams, it considered options other than additional MBOs.

A derivative of Stockholm's A24 was considered,[17] as was a modernized Gullfisk with Vickers motors and two variations of Hägglund trams.

The company considered multiple-unit trams, which would allow for faster speeds, but opted against this due to an increased fault rate and higher maintenance.

The remaining eighteen trailers would be built by Strømmens Verksted, due to lack of capacity at Høka.

The trailer had left-hand drive, but by simply running it "backwards" the doors were placed on the right side.

[23] The city council voted in 1960 to gradually close down the tramway and replace it with the metro and diesel buses.

[30] To cut costs, Oslo Sporveier considered during the late 1960s if it could introduce one-man operation and abolish the conductor during off-peak hours.

Except for being underpowered, making them unsuitable for service on the Ekeberg Line, they worked well and Oslo Sporveier therefore decided to retire the Chickens and replace them with additional MBG and TBG trams and trailers.

[38] In a move to retire the last Gullfisk before their next main revision, Oslo Sporveier rebuilt some of the SM53 units to allow them again to run on the suburban lines.

This time vertical suspension was installed between the bogies and axle box, finally solving the issue with the swaying.

This resulted in seven used S27 trams being bought from Gothenburg and designated TBG and entering service between 27 November 1985 and 16 January 1986.

The work involved rebuilding the front, installation of new doors and interior, and a new chopper-based controller and new electronics.

Consultants had concluded that Oslo Sporveier should introduce a uniform red color with dark blue detailing on all modes of transport: buses, metro trains and trams.

[43] As part of construction work at Storo and Sinsen the tramway decided to lease used M25 trams from Gothenburg, designated SM91.

[45] In 1997 the high-voltage cable issue was regarded as so severe that the company decided that they either would have to be replaced for the trams scrapped.

Each motor produced an output of 45.6 kilowatts (61.2 hp), which allowed for a maximum speed of 60 kilometers per hour (37 mph).

A fully loaded tram and trailer could reach a speed of 40 kilometers per hour (25 mph) up the steepest hills.

The reason for introducing a wheel was to allow the driver to man it with either hand and give it a more ergonomic location, as the motormen's job was to a greater degree to manoeuver the tram in traffic rather than a more technical control of the vehicle.