The Delhi Metro (Hindi: दिल्ली मेट्रो Dillī Meṭro) is a rapid transit system serving Delhi, Gurgaon and Noida in the National Capital Region of India. The network consists of six lines with a total length of 189.63 kilometres (117.83 mi) with 142 stations of which 35 are underground. It has a combination of elevated, at-grade and underground lines and uses both broad gauge and standard gauge rolling stock.