Esplanade Line 2 metro station in Kolkata, India: planning, design and construction

Esplanade metro interchange in Kolkata, India, is at the junction of the existing north–south Line 1 and the nearly completed east–west Line 2. The interchange will also serve as a terminal for Line 3, which is under construction. As the Line 2 tunnels cross below the diaphragm walls of the existing part of the Line 1 station, the new Line 2 station is one of the deepest in the country. Accommodating the peak passenger load of three lines and providing smooth transfers was also a challenge for designers. Building the large, deep structure in deltaic soil was undertaken using top-down construction, with additional sprayed concrete lining tunnels required to remove piled obstructions.