mi) of tracks through 255 stations. ZET, the major transit authority in Zagreb, ordered 210 new, 100% low-floor trams from Croatian consortium Crotram. As of 2010, all of these locally produced, low-floor Crotram trams have been delivered, with a mixture of vehicle types in operation, including Czech Tatra Cars and various locally produced trams. Zagreb is one of the few tram networks in the world where most of the operations run at the kerb. The only other Croatian city with trams still in operation is Osijek. The first tram route commenced in 1884 (connecting the railway station and city square) and trams have been running since. Between 2006 and 2007, the trams were refurbished and modernised. Two lines presently exist, with another two extensions planned, doubling the network length. Dubrovnik, Opatija, Pula, Rijeka and Velika Gorica previously also operated trams. Czech Republic The Czech Republic is well known for its extensive tram infrastructure, with trams often being present even in small cities. The largest network is in Prague, with 141 kilometres of track and 35 lines, including 9 night lines. Other cities with tram systems are Brno, Ostrava, Plzeň, Olomouc, Most and Litvínov (common network), Liberec (including intercity line to Jablonec). Tram networks in nine other cities were closed down mainly during the 1960s and replaced with trolleybuses or buses. Before changes in 1989, ČKD Tatra in Prague was the largest tram producer in the world, mainly exporting its trams to Soviet Bloc countries. Production was definitely stopped in 2001, after ČKD was sold to Siemens AG. The tradition of tram production is continuing with Škoda Transportation, Inekon and PRAGOIMEX. Denmark In Aarhus, Denmark the Aarhus Letbane a new tramway is combined with converted local railways, operating since December 2017. In Odense, Denmark the Odense Letbane a new tramway, operating since 28 May 2022. In Copenhagen, Denmark construction has started on a new tramway, expected to start operation in 2025. Estonia In Estonia, trams are used only in the capital, Tallinn. There has been a growing tram network in Tallinn since 1888, when traffic was started by horse-powered trams. The first line was electrified on 28 October 1925. Estonian-built electric trams were also used, with some gas-powered trams having been used in the 1920s and 1930s. The last part of the system to be electrified was the spur to Kopli in 1951, which was also converted to double track at