September 2021 - Tunneling works underway; April 2020 - IRCON invites bids for construction of two railway Tunnels T12 and T13; February 2016 - Supreme Court gave nod for construction of line after project opposed by wildlife activists and environmentalists; Construction commenced in March 2010; Line will include 14 tunnels, longest being 5.11 km; Project Value - INR40.85bn