The Siemens C651 is the second generation electric multiple unit rolling stock in operation on the North South and East West lines of Singapore's Mass Rapid Transit (MRT) system, manufactured by Siemens (SIE) under Contract 651. A total of 114 cars consisting of 19 train-sets were purchased in 1992 and introduced into service from 1995 onwards. These trains were built by Siemens in Austria.