Swedish three-foot gauge railways (Swedish: "trefotsbanor") are railways with the gauge 891 mm (2 ft 11 3⁄32 in), or 3 Swedish feet in the old Swedish measurement system. Railways with this gauge have only existed in Sweden. This was the most common narrow gauge in Sweden. Sweden once had some fairly extensive narrow-gauge networks, but most narrow gauge railways are now closed. Some were converted to standard gauge (the latest one was KBJ, Kalmar - Berga Järnväg, between Berga and Kalmar in the 1970s) and some remain as heritage railways.