Indian Railways intends to four-lane roughly 11,000 km of its High-Density Network (HDN) to raise capacity and ease congestion. Its seven high-density routes, Delhi–Howrah, Howrah–Chennai, Chennai–Mumbai, Mumbai–Delhi, Delhi–Chennai, Mumbai–Howrah and Delhi–Guwahati, carry about 41% of rail traffic on only around 16% of the network. Separately, Kavach 4.0, the indigenous Automatic Train Protection (ATP) system, is now commissioned on 2,490 route km of the Delhi–Mumbai and Delhi–Howrah corridors, with sharper train-location accuracy, better signal data in large yards and integration with Electronic Interlocking Systems.