October 1 in Swedish History
1950: the first line extension with real subway trains of Stockholms tunnelbana (the Stockholm subway) opens. The line runs south from Slussen to Hökarängen in the direction of Farsta.

The decision to build a ”tunnelbana” in Stockholm had been made already in 1931, and during the following years routes were built with near metro standard, but operated with trams only. The first tunnel was inaugurated in 1933: The first underground subway tunnel is inaugurated in Stockholm. After the first line had been established, two more lines extending from Slussen (via Gullmarsplan, then Johanneshov) were opened. In 1952, a second system from Hötorget to the western suburbs was opened.

Then in 1957, the two parts were connected via the Central station (at T-Centralen) and the Old Town (at Gamla stan subway station), forming the Green Line. The Red Line was opened in 1964, with two lines going from northeast to southwest via the city center. The third and final system, the Blue Line, was opened in 1975, with two lines running northwest from the city center.
The latest addition to the whole network, Skarpnäck station, opened in 1994.