The Ultra Low Floor tram (ULF) is a low floor tram currently operating only in Vienna, Austria. It has the lowest floor-height in the world.

In contrast to regular low floor trams, the floor in the interior of ULF is low enough to be at the same height as a sidewalk (about 18 cm above the road surface), which makes access to trams particularly easy for passengers in wheelchairs or with perambulators. This configuration required a completely new design of the undercarriage, and the axles had to be replaced by a complicated electronic steering of the traction motors. Auxiliary devices are installed largely under the roofs of the cars.

The ULF technology went into testing in the early 1990s. Since 1998, ULFs have been in use in Vienna's tram network; they were built by a consortium composed of Siemens and Elin in Vienna. As of June 20, 2004, 128 cars were in operation. An additional 152 are to enter into service in mid-2006. The order was placed in mid-2004. The producers also hope for orders from other cities, the prospects for which now seem to be improved in light of the technical problems with the Combino.

An ultra low floor tram (ULF) in Vienna, Austria (July 2003)

See also

• List of transport topics
• Road transport
• Rail transport
• Combino