Hindustan Construction Company (HCC) completed the south-bound tunnel between CSMT and Mumbai Central stations on August 2, 2019. With this, HCC became the first contractor among all packages to complete the entire length of a tunnel. With an average drilling rate of around 8.2 m per day, the 3.82-km long tunnel from CSMT to Mumbai Central via the station boxes at Kalbadevi, Girgaum and Grant Road, was completed surmounting various challenges, according to the company. The construction of station buildings is currently underway. All the station buildings are unique in design. While the CSMT station is completely a cut and cover station, the remaining three stations would be made by NATM method.