The Central Railway has approved the construction of a fourth railway line along the Karjat–Panvel corridor to enhance connectivity to the upcoming Navi Mumbai International Airport. The 29-kilometre stretch is expected to significantly improve regional rail access, particularly for commuters from Pune and nearby areas.Estimated to cost Rs 4.91 billion, the project is outlined in the final Detailed Project Report (DPR) submitted to the Railway Board on 7 April. A Central Railway spokesperson confirmed the decision, stating the fourth line will help decongest the corridor and allow greater frequency of suburban trains.Currently, the route has only one operational track that mainly serves freight trains and a limited number of long-distance services. Two suburban-dedicated lines under construction by Mumbai Rail Vikas Corporation (MRVC) are expected to be completed by December 2025. The fourth line will supplement these as part of the Mumbai Urban Transport Project 3 (MUTP-3), aimed at facilitating smoother transit between Pune and the Navi Mumbai airport zone.Authorities see the move as a transformative step. By strengthening the rail network and improving links to key urban nodes such as Panvel, Karjat, and the Navi Mumbai Airport Influence Notified Area (NAINA), the project supports the decentralisation of Mumbai’s urban sprawl.Three local trains are reportedly ready to begin operations along the Karjat–Panvel route once the upgraded infrastructure is in place. The project is viewed as vital to Mumbai’s broader urban mobility strategy, aiming to ease congestion on the city’s core lines while encouraging development in outlying regions.