Work on a 909.0-metre tunnel, the first for the Delhi Metro's Phase-III, was Thursday completed at the upcoming Janpath Metro Station on the three-km underground line between Central Secretariat and Mandi House, an official said.
A 30-foot tunnel boring machine (TBM) was lowered into the ground close to Chelmsford Club near the Central Secretariat Metro Station Jan 31 and the nearly one-km tunnel up to the Janpath Metro Station was dug in six months.
The Central Secretariat and Mandi House Metro link would be ready by 2014.
"The tunnel was made almost 18 metres below the road surface and the excavated earth was deposited at the Sarita Vihar depot," a Delhi Metro official said.
"The first breakthrough of a tunnel is always special and significant. This breakthrough for a tunnel was achieved as per schedule and without any bottlenecks," said Delhi Metro chief Mangu Singh.
With the completion of Phase-III in 2016, the DMRC would cover almost 70 percent of Delhi. Delhi Metro now makes over 2,400 trips a day, covering about 70,000 km and carrying around 1.8 million passengers on a week day.