The Bulgarian capital Sofia (about 1.2 million inhabitants) is the only city of Bulgaria with rail-bound public transport. The tram network has a system length of approx. 150 kilometres. Some 40 km of it are standard-gauge, the rest has a track gauge of 1,009 mm. It is operated by 'Stolichen Elektrotransport EAD' (Столичен електротранспорт ЕАД).
Sofia also has a 40 kilometre long metro system operated by Metropoliten EAD (Метрополитен ЕАД). The Metro is quite young, the first route was opened in 1998.