Narrow-gauge railways in Sweden
Sweden once had some fairly extensive narrow-gauge networks, but most narrow-gauge railways are now closed. Some were physically converted to 1,435 mm (4 ft 8+1⁄2 in) standard gauge (the latest one the line between Berga and Kalmar in the 1970s) and some remain as heritage railways.
Source: Wikipedia — Narrow-gauge railways in Sweden (CC BY-SA 4.0)