route, only covering from Schottentor to its terminus at Antonigasse in the district of Währing. From end of May 2021 until autumn 2023 the new line U2Z, replacing underground line U2 during construction, is slightly shorter. Fleet The Vienna tram fleet consists of both high-floor and low-floor vehicles. On weekdays, some lines operate with a combination of high and low-floor trams, but on weekends (especially Sundays), only a limited number of high-floor trams are used on lines D, 2, 5, 25, 31, 38 and VRT. Low-floor trams were successively introduced from 1995, most recently on line 33 in September 2011. This allowed all tram stops in Vienna to be served by such vehicles, thus providing step-free travel throughout the entire network. High-floor trams From 1959, articulated tramcars of Type E were used. However, it became difficult to operate these trams with trailer cars due to their underpowered motors, necessitating their replacements soon afterwards. The successors, the Type E1 trams, were first delivered in 1966. They were of similar appearance to their predecessors, but equipped with more powerful motors. The Type E remained in service until 2007, most recently on lines 10 and 62. E1 had its last day in regular service on July 1, 2022, this on line 30. After production of the E1 ceased in 1976, a further successor generation, the Type E2, was developed, and has been in service since 1978. The trailer fleet constructed to match the tramcars is made up of Types c4 for the E1 tramcars, and Type c5 for E2 tramcars. On less frequented lines, the tramcars also operated without trailers. Following a number of serious accidents, the majority of the high-floor trams have been fitted with electric door edge sensors and rear-view mirrors. Tramcars (not air-conditioned) Type E1 – originally 338 cars – built 1966–1976; seats: 40, standing places: 65. (withdrawn as of July 1, 2022) Type E2 – 118 cars (June 2021) (originally 122) – built 1978–1990; seats: 44, standing places: 58 (withdrawal planned for 2026) Trailers (not air-conditioned) Type c4 – originally 73 – built 1974–1977 (June 2021); seats: 31, standing places: 43 (withdrawn as of July 1, 2022, together with tramcar E1) Type c5 – 115 cars (originally 117) – built 1978–1990; seats: 32, standing places: 39 Low-floor trams Ultra Low Floor (ULF) The articulated Ultra Low Floor (ULF) trams, built by a consortium composed of Siemens and ELIN, come