Delhi is a major junction in the Indian railway network and is the headquarters of the Northern Railway. The main railway stations are New Delhi, Old Delhi, Hazrat Nizamuddin, Anand Vihar, Delhi Sarai Rohilla and Delhi Cantt. The Delhi Metro, a mass rapid transit system built and operated by Delhi Metro Rail Corporation (DMRC), serves many parts of Delhi and the neighbouring cities Ghaziabad, Faridabad, Gurgaon and Noida. , the metro consists of eight operational lines with a total length of  and 214 stations, and several other lines are under construction. The Phase-I 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. In addition to the Delhi Metro, a suburban railway, the Delhi Suburban Railway exists.