Calcutta: The west-bound East-West Metro tunnel went past Writers' Buildings early on Sunday without harming the 18th century structure that engineers had fortified before the operation.

The tunnel-boring machine passed 19 metres underground and barely 2.5 metres from the periphery of Bengal's seat of power, which has been under renovation since 2013.

The machine being used for the east-bound tunnel - like the other one, it is approaching from the Howrah side - will pass about 13 metres away from Writers'.