The Renigunta-Nandalur sector electrification was completed in 2006. The Nandalur-Guntakal sector was electrified by Dec 2013. The Chennai Beach-Tambaram sector was electrified with DC overhead line in 1931 and was converted to 25 kv AC in 1967. The Puratchi Thalaivar Dr. M.G. Ramachandran Central Railway Station-Tiruvallur sector, as well as the Basin Bridge-Chennai Beach sector were electrified in 1979-80. The Tiruvallu-Arakkonam sector was electrified in 1982-83, Arakkonam-Tiruttani sector in 1983-84 and the Tiruttani-Renigunta sector in 1984-85. The Kalyan-Pune-Daund-Wadi-Secunderabad-Kazipet line and the Wadi-Raichur-Adoni-Arrakonam-Puratchi Thalaivar Dr. M.G. Ramachandran Central Railway Station line are classified as 'Group B' lines and can take speeds up to 130 km/h. However, the stretch between Chhatrapati Shivaji Maharaj Terminus and Kalyan is classified as 'Group A' lines, where trains can take speed up to 160 km/h. Pune, Solapur and Puratchi Thalaivar Dr. M.G. Ramachandran Central Railway Station, on this line, are amongst the top hundred booking stations of Indian Railway. Mumbai-Chennai line is a part of Diamond Quadrilateral.