Kristiania Elektriske Sporvei

A/S Kristiania Elektriske Sporvei or KES, nicknamed the Blue Tramway (Norwegian: Blåtrikken), was a company which operated part of the Oslo Tramway between 1894 and 1924. It built a network of four lines in Western Oslo, the Briskeby Line and the Frogner Line which ran to Majorstuen, and two other consecutive lines, the Skøyen Line and the Lilleaker Line. These all connected to a common line through the city center which terminated at Jernbanetorget.

KES was established as the second tram operator in Oslo (then known as Kristiania). When it commenced services it was the first electric tramway in Scandinavia. It originally opened the Briskeby Line and the Skøyen Line to Skillebekk using a fleet of Class A trams. Later the company also ordered Class U and Class SS trams, for a total 78 motor cars and 66 trailers. Skøyen was reached in 1903. The first part of the Frogner Line opened in 1902, and it was completed in 1914. The Lilleaker Line was built to Lilleaker in 1919. KES and its competitor, Kristiania Sporveisselskab (KSS) were both taken over by Oslo Municipality in May 1924 and became Oslo Sporveier. The take-over did not include the Lilleaker Line and this part of the operation continued as Bærumsbanen.