The Ultra Low Floor tram (ULF) is a low-floor tram operating in Vienna, Austria and Oradea, Romania, with the lowest floor-height of any such vehicle. In contrast to other low-floor trams, the floor in the interior of ULF is at sidewalk height (about 18 cm or 7 inches above the road surface), which makes access to trams easy for passengers in wheelchairs or with baby carriages. This configuration required a new undercarriage. The axles had to be replaced by a complicated electronic steering of the traction motors. Auxiliary devices are installed largely under the car’s roof.
The ULF technology went into testing in the early 1990s. Since 1998, ULFs have been in use on Vienna's tram network, built by a consortium composed of Siemens and Elin in Vienna. As of mid-2008, 302 cars were in operation (150 cars since mid-2006, and another 152 as of 2007).
Siemens ULF trams were introduced in Oradea, Romania on 24 April 2008.[1]
| City / Operator | Type designation | Built in | Number of vehicles | Length | Width | Weight (empty) | Maximum power |
|---|---|---|---|---|---|---|---|
| Vienna, Austria/Wiener Linien | A | 1995 (prototype), 1997 | 50 | 24.20 | 2.40 | 30 t | 6 x 60 kW |
| Vienna, Austria/Wiener Linien | A1 | 2007– | 80 | 24.20 | 2.40 | 30 t | 6 x 36 kW |
| Vienna, Austria/Wiener Linien | B | 1995 (prototype), 1998 | 100 | 35.30 | 2.40 | 43 t | 8 x 60 kW |
| Vienna, Austria/Wiener Linien | B1 | 2009– | 70 | 35.30 | 2.40 | 43 t | 8 x 36 kW |
| Oradea, Romania/ OTL | A1 | 2008–2009 | 10 | 24.20 | 2.40 | 30 t |