Mumbai, Feb. 3 -- The Mumbai-Ahmedabad Bullet Train project achieved a major construction milestone on Tuesday with a construction breakthrough of a second mountain tunnel in Maharashtra's Palghar district.

With a length of 454 metres and width of 14.4 metres, the tunnel will accommodate both up and down tracks for the project.

"At 11.14am, blasting took place at MT-6. This was the second breakthrough of a mountain tunnel in less than a month with the previous one at MT-5 on January 2," said an official from National High Speed Rail Corporation.

Seven mountain tunnels are currently under construction in Palghar district. As of January 27, at least 334km of viaducts, 17 river bridges, and 12 major crossings over national highways, railw...