For the first time after quadrupling the Chhatrapati Shivaji Maharaj Terminus (CSMT)-Thane railway a century ago, an ambitious plan to build a new 17.5-km rail corridor all the way to CSMT in south Mumbai has called for land acquisition and demolition of over 700 structures, railway buildings, rebuilding structures and even diverting the old harbour line to P D’Mello Road. 

As part of the project, the first major thing to be taken up would be replacement of the Sion road overbridge (RoB). The bridge will be shut for traffic as it will need to be rebuilt to accommodate two new lines below it.