Storstockholms Lokaltrafik, or more formally Aktiebolaget Storstockholms Lokaltrafik (Greater Stockholm Local Transit Company), is the organisation running all of the land based public transport systems in Stockholm County. It was previously known as Stockholms Lokaltrafik and is commonly referred to as SL. History SL has its origins in AB Stockholms Spårvägar (SS), a city-owned public transit company which started in 1915 by the City of Stockholm with the aim to deprivatize the two separate private tramway networks into one more efficient company. SS would in the late 1920s also acquire private motorbus companies. The first part of the Stockholm Metro was opened in 1950. SS was renamed to SL in January 1967 when the metro, local train, and bus operations in Stockholm County were merged into a single organisation under the supervision of Stockholm County Council. The different mass transit systems within the County had until then been run by different organisations, Statens Järnvägar, private companies and companies owned by the local municipalities. In 1993 SL began to use independent contractors for the operation and maintenance of the different transport systems. For bus traffic the operators own the buses, but for rail bound traffic SL own the trains, and the contractors operate them. Tickets by one measure—single ticket price for a journey—Stockholm has the most expensive-to-use public transport in the world. SL's tickets SL has two main forms of tickets. Both are used for all SL public transport within Stockholm County. Travel card — valid during a specified period of time, from 24 hours up to a year, depending on the card. Single journey ticket — valid for 75 minutes from activation, within Stockholm County. Single journey tickets are mainly purchased and loaded onto an SL Green card, but can be bought also by SL app or by contactless payment card. In either case, the ticket is loaded onto a Green SL RFID card that is scanned at the start of the first journey. It is possible also to use a contactless payment card (Mastercard, Maestro, Visa and Visa Electron) to buy a single ticket (75 min). As you board a public transport vehicle, you will be required to validate your trip every time by swiping the payment card at the rectangular validators in the front of the vehicle. If you hear a beep and see a green light, your trip has been validated. Regardless of the ticket used, journeys