Metro-3: Special tracks to protect heritage buildings

MUMBAI: The Mumbai Metro Rail Corporation (MMRC) is in the process of procuring special track components for the fully underground Metro-3 line to protect heritage structures and dilapidated buildings from vibrations. This is the first such initiative in India.

The decision comes against the backdrop of some old buildings in south Mumbai developing cracks owing to Metro-3 works. According to MMRC, the 33.5-km Colaba-bandra-seepz corridor is being built below 100plus monumental structures and old buildings in south Mumbai. Once the corridor is operational, these structures will be at a constant risk of damage, owing to vibrations caused between the wheels and tracks.

Officials said MMRC is procuring a track system which will have twin-block sleepers. A sleeper is a rectangular support between the rails on the track. A regular railway track has only one continuous sleeper between two rails. For Metro-3, the twinblock sleepers are designed with concrete blocks, which will have a rubber boot fitted with resilient pads to absorb the vibrations. These low-vibration tracks have been used in London, Sweden, Moscow and Zurich.

SK Gupta, director (projects), MMRC said, “A regular Metro track can absorb around 5 to 7 Vdb [vibration measurement], while this system can absorb 22Vdb over and above the 5-7 Vdb. It is also easier to undertake the maintenance of these components. We are looking at starting the track-laying work by June.”

Officials said regular tracks will only be used at the depot which will have a station at-grade (ground-level station).

In November, two buildings in Mahim developed cracks, allegedly owing to the works undertaken at the nearby Sitladevi Metro station. In 2017, the JN Petit Institute in Fort had filed a petition in the Bombay high court, alleging that an ornamental feature of the building collapsed owing to vibrations caused by Metro-3 works.