In 1899, Oslo Municipality established KKS to build and operate three tram lines.

[4] On 26 January 1901, a new connection line through Dronningens gate was built from Tollbugata to Kirkeristen, and the company no longer needed to lease tracks from Kristiania Elektriske Sporvei in the city center.

[5] The entire Rodeløkka Line was rebuilt with double track in 1938.

In December 1940, a service extension of the Rodeløkka Line was built from Rodeløkka to Søndre Åsen, operated by the Oslo trolleybus, remaining in service until 14 January 1945.

[6] The bus operation had been more expensive than the tram, and a double track line was built from Carl Berners plass through Dælenenggata to Rodeløkka.

The balloon loop was built around the block of Dælenengata, Fagerheimgata, Marstrandgata and Københavngata.

From 29 June 1924, after the takeover of Oslo Sporveier, the headway was changed to fifteen minutes.