The El 3 and El 4 had about the same characteristics and used for the same purpose and ordered simultaneously; choosing two models like this is atypical for railway companies because of higher maintenance costs.
By 1922 SJ had placed an order on the new Of-locomotives, yet NSB chose to base the El 3 on the older Oe.
They only served on the Norwegian lines until 1949, after which they were where put into through trains to Kiruna.
In 1953-54 the locomotives were rebuilt to three triple-engine sets and supplemented with eight El 12.
When LKAB chose to increase train weights more in the late 1960s, NSB responded with the order of the El 15.