The project - scheduled for completion within five years - will supplement the existing 376km suburban rail network in India's commercial capital with an additional 28km line from Panvel to Karjat and a 3km elevated extension from Airoli to Kalwa. Phase 3 also includes four-tracking of the 63km Virar - Dahanu Road line, procurement of 565 new EMU cars, and investment in trespass control measures.

The Mumbai suburban railway network currently serves five corridors, with more than 2900 services carrying a total of 8 million passengers per day.

Construction of two additional tracks on the Virar - Dahanu Road line will enable the extension of suburban services from Churchgate to Dahanu Road, while the Panvel-Karjat line will provide an alternate route from Karjat to Chhatrapati Shivaji Terminal (CST) via Panvel, shortening the distance between these stations by 23km. CST - Karjat journey times will be reduced by 35-40 minutes for slow trains.

Currently, commuters from Kalyan to Vashi or Panvel have to change to the Trans-Harbour link at Thane, resulting in heavy congestion at this station. The Airoli - Kalwa line will bypass Thane station, relieving pressure on the network in this area.