50% Metro tunnelling complete in 19 months

The underground corridor, which is expected to provide another north-south rail service and an alternative to the suburban railway requires 56km of tunnelling for the twin passageways.

The Mumbai Metro Rail Corporation (MMRC) has completed 50% of the tunnelling work for the city’s first underground Metro line (Colaba-Bandra-Seepz). The milestone was achieved in 19 months after tunnelling commenced for the 33.5-km Metro-3 line in November 2017, MMRC, the executing agency of the project, announced on Monday.

With 17 tunnel boring machines (TBMs) working simultaneously, 28km of this stretch has already been finished. Image used for representational purpose only. ((Photo by Praful Gangurde/ Hindustan Times))

The underground corridor, which is expected to provide another north-south rail service and an alternative to the suburban railway requires 56km of tunnelling for the twin passageways. With 17 tunnel boring machines (TBMs) working simultaneously, 28km of this stretch has already been finished.

According to Ashwini Bhide, managing director of MMRC, the tunnelling under Mumbai’s heritage buildings, old residential complexes, and existing elevated Metro line, has been a “daunting task” due to the geological conditions.

The average tunnelling, as per data provided by MMRC, is 47.5m per day, with nearly 100 workers per TBM involved in the process.

“In all, 19,504 segment rings have been used to complete 28km of tunnelling. Further, 19 more breakthroughs [point to point tunnelling] are awaited through the 33.5-km Metro 3 alignment,” said SK Gupta, director (projects), MMRC. Meanwhile, work of underground station construction, along with excavation, concourse level, columns and wall construction are progressing quickly.“We are looking to complete the Rs 23,136-crore project as scheduled with the help of the CM’s War Room and multiple stakeholders,” said Bhide.