What is the local Norwegian name for the Oslo Metro?

What is the local Norwegian name for the Oslo Metro? T-banen.

T-banen is the ordinary Norwegian name for Oslo’s metro system; the full form is T-banen i Oslo. The word is short for tunnelbane, meaning “tunnel railway,” although much of the network runs above ground rather than underground.

The system developed from older suburban tramways. The Holmenkollen Line opened in 1898, and the first underground section, reaching Nationaltheatret, opened in 1928. Modern metro operation began in 1966, when eastern suburban lines were converted and connected with the central network.

Today, the T-banen links Oslo’s city centre with residential districts and also extends into neighboring Bærum. Its five lines converge through the central area, while the Common Tunnel carries trains beneath the city. Readers sometimes confuse T-banen with Oslo Tunnelbane, another valid descriptive name, but T-banen is the standard local name expected by this question.