connections and interconnections. This period marked the beginning of widespread rail transportation in Austria–Hungary, and also the integration of transportation systems in the area. Railways allowed the empire to integrate its economy far more than previously possible, when transportation depended on rivers. After 1879, the Austrian and the Hungarian governments slowly began to renationalize their rail networks, largely because of the sluggish pace of development during the worldwide depression of the 1870s. Between 1879 and 1900, more than of railways were built in Cisleithania and Hungary. Most of this constituted "filling in" of the existing network, although some areas, primarily in the far east, gained rail connections for the first time. The railway reduced transportation costs throughout the empire, opening new markets for products from other lands of the Dual Monarchy. In 1914, of a total of of railway tracks in Austria, (82%) were state-owned. Railways in Transleithania The first Hungarian steam locomotive railway line was opened on 15 July 1846 between Pest and Vác. In 1890 most large Hungarian private railway companies were nationalized as a consequence of the poor management of private companies, except the strong Austrian-owned Kaschau-Oderberg Railway (KsOd) and the Austrian-Hungarian Southern Railway (SB/DV). They also joined the zone tariff system of the MÁV (Hungarian State Railways). By 1910, the total length of the rail networks of Hungarian Kingdom reached , the Hungarian network linked more than 1,490 settlements. Nearly half (52%) of the empire's railways were built in Hungary, thus the railroad density there became higher than that of Cisleithania. This has ranked Hungarian railways the 6th most dense in the world (ahead of Germany and France). Electrified commuter railways: A set of four electric commuter rai lines were built in Budapest, the BHÉV: Ráckeve line (1887), Szentendre line (1888), Gödöllő line (1888), Csepel line (1912) Tramway lines in the cities Horse-drawn tramways appeared in the first half of the 19th century. Between the 1850s and 1880s many were built : Vienna (1865), Budapest (1866), Brno (1869), Trieste (1876). Steam trams appeared in the late 1860s. The electrification of tramways started in the late 1880s. The first electrified tramway in Austria–Hungary was built in Budapest in 1887. Electric tramway lines in the Austrian Empire: Austria: Gmunden (1894); Linz, Vienna (1897); Graz (1898); Trieste (1900); Ljubljana (1901); Innsbruck (1905); Unterlach, Ybbs an der Donau (1907); Salzburg (1909); Klagenfurt, Sankt Pölten (1911); Piran (1912) Austrian Littoral: Pula