Ultra Low Floor (a low-floor tram operating in Vienna) had five type designations between 1995 and 2009.
The Ultra Low Floor tram (ULF) is a low-floor tram operating in Vienna, Austria and Oradea, Romania, built by a consortium composed of Siemens and in Vienna. A 1995 (prototype), 1997 A1 20072015 B 1995 (prototype), 1998 B1 2009 A1 20082009 
