MUMBAI, May 16 -- The state's push to develop the Mumbai Metropolitan Region (MMR) will see the expansion of the suburban rail corridors on both the Central and Western railways. On the agenda are new lines linking the Navi Mumbai airport with the MMR, separating suburban and long-distance train services, and extending rail connectivity from Dahanu to the proposed Vadhvan port, billed as India's largest port, in Palghar district. The Union Railway Ministry has asked the Central and Western railways to carry out surveys and studies for these new suburban rail lines. On the Central Railway, the ministry wants new lines connecting the Navi Mumbai International Airport (NMIA), the additional lines on the Asangaon-Kasara section, the Badlapur-Karjat section, and to separate suburban and long-distance trains. The ministry also wants a 75-km-long, third rail line on the Panvel-Roha route, on the edge of MMR. On the Western Railway, the railway will survey the Dahanu-Vadhavan Port line for expansion. This is the first time the railways are considering connecting airports with suburban rail lines, alongside the metro rail. Railway sources in Mumbai said they have been asked to survey locations for two separate rail lines connected to NMIA. The first is a 4-km-long line from Khandeshwar station to NMIA on the CSMT-Panvel Harbour Line and the other is a 1-km-long line from Targhar to NMIA on the Seawoods/Belapur-Uran rail corridor. The estimated cost of the survey for the two proposed rail extensions is Rs.10 lakh. The railways will also execute two projects to augment capacity. One is the fourth line on the Asangaon-Kasara route, an extension to the ongoing work on the Kalyan-Asangaon line. The Asangaon-Kasara line will be 35-km long and will separate suburban and long-distance trains, thus addressing issues of congestion and delays. Land acquisition for the 32-kms-long Kalyan-Asangaon corridor is underway. Similarly, the Central Railway will study the possibility of adding three to four lines on the Badlapur-Karjat section, which has been approved under the PM Gati Shakti scheme. This rail corridor will be implemented under the Mumbai Urban Transport Project phase-3A at a cost of Rs.1,510 crore. It will benefit the towns of Badlapur, Ambarnath and Ulhasnagar as suburban services will increase once suburban and long-distance lines are separated. The railways also plan to link the proposed Vadhavan Port to a rail line from Dahanu. An official with the Western Railway said this would bring long-term benefits as there will also be a dedicated freight corridor near the port....