NSB El 9 is a retired class of three electric locomotives built by Thune for the Norwegian State Railways (NSB), with electrical equipment from Norsk Elektrisk & Brown Boveri (NEBB) and Per Kure.

The locomotives were delivered in 1947 after a three-year delay caused by wartime sabotage in response to the German occupation of Norway.

They had a power output of 712 kilowatts (955 hp), a tractive effort of 108 kilonewtons (24,000 lbf) and a maximum speed of 60 kilometres per hour (37 mph).

[2][3] The Flåm Line is 20.20 kilometers (12.55 mi) long, had a maximum gradient of 5.5. percent, a minimum curve radius of 130 meters (430 ft) and a maximum speed of 40 km/h (25 mph) uphill and 30 km/h (19 mph) downhill.

[5] On 28 March 1940, NSB sent an invitation to tender for two multiple units which would be similar to Class 64.

However, NSB abandoned the plans and instead signed an agreement on 4 October 1940 for delivery of three electric locomotives.

[8] By 1944, by which time Norway was occupied by Germany as part of the Second World War, overhead wire had been installed on the Flåm Line.

[8] Because of the Allied bombing of Germany, Per Kure was thought to become part of a decentralized production chain and would be set to assemble aircraft engines.

Osvald considered the plant a legitimate target and on 30 May 1944, the factory was blown up and the transformers severely damaged.

Lack of spare parts and limited reliability accelerated the need to replace the units in scheduled trains.

[14] The locomotives each have four NEBB EDTM423 motors, giving a combined power output of 712 kilowatts (955 hp).

[8] The locomotives have a maximum speed of 60 km/h (37 mph) and a tractive effort of 108 kilonewtons (24,000 lbf).

As a backup, the units are equipped with a carborundum track brake on each side of the bogies.