It has a combination of elevated, at-grade, and underground lines, and uses both broad gauge and standard gauge rolling stock. Four types of rolling stock are used: Mitsubishi–ROTEM Broad gauge, Bombardier MOVIA, Mitsubishi–ROTEM Standard gauge, and CAF Beasain Standard gauge. The Phase-I of Delhi Metro was built at a cost of US$2.3 billion and the Phase-II was expected to cost an additional . Phase-II has a total length of 128 km and was completed by 2010. Delhi Metro completed 10 years of operation on 25 December 2012. It carries millions of passengers every day.