<h1>Kolkata Metro Purple Line tunnelling begins with boring machine operations starting underground construction phase</h1> Tunnelling work commenced for Kolkata Metro's Purple Line at a location, with a tunnel boring machine beginning operations following a ceremony attended by railway officials and local representatives. The Purple Line will connect two major stations and is currently operational between two intermediate points. The elevated section transitions to underground beyond one station. Tunnelling work is expected to complete by end-2026. Two machines will construct twin tunnels using earth pressure balancing technology suitable for local soil conditions. The line will eventually connect with existing Blue and Green metro lines at a central station.