L&T Casts First Tunnel Segment works of Kolkata Metro Line-3

Kolkata, India (Metro Rail Today): In a notable advancement for Kolkata’s urban transit infrastructure, Larsen & Toubro (L&T) has initiated the casting of the first batch of tunnel ring segments for the 15.215 km Line-3, also known as the Purple Line. This progress marks the commencement of concrete pouring for the 5.05 km underground package UG1, a critical section of the metro line.

Project Scope and Specifications

L&T has been entrusted with the construction of Line-3’s only underground section, stretching from Mominpur to Esplanade. This segment will feature twin tunnels and four underground stations at Kidderpore, Victoria Memorial, Park Street, and Esplanade. The Esplanade station will serve as Kolkata’s first three-line interchange, connecting the Blue Line (Dakshineswar to Kavi Subhash) and the Green Line (Howrah Maidan to Sector V).

Casting Yard and Production Details

L&T’s casting yard for UG1 is strategically located in the Sarkarpool neighborhood of Maheshtala, near Line-3’s Majerhat Station. From preliminary calculations, it is estimated that approximately 4,000 segments will be produced to construct the twin tunnels, which will have an inner diameter of 5.8 meters. This extensive production process is crucial for the structural integrity and longevity of the metro tunnels.

Construction and Contract Details

In June 2023, L&T was awarded the Rs. 2447 crore civil construction contract for the 5.05 km Package UG1 by Rail Vikas Nigam Ltd (RVNL), after emerging as the lowest bidder. This section includes roughly 500 meters on the northern end, between Esplanade and Park Street, which will be constructed using the cut and cover method.

Technical Specifications

Each reinforced concrete tunnel ring is designed to be 1,400 mm wide and 275 mm thick, comprising five segments plus a smaller ‘key’ segment. This design ensures the strength and stability required for safe and efficient metro operations.

Commencement of Construction

L&T officially began construction work for this package at the Victoria Memorial Station site in Maidan in May 2024. Preparatory work for the tunnel boring machine (TBM) launch shaft at St. Thomas School in the Kidderpore neighborhood started in late June 2024. Metro Rail Kolkata confirmed that two Herrenknecht TBMs will be deployed for this package, with tunneling work expected to begin no sooner than Q2 2025.

Projected Timeline

Given the complexity and scale of the project, the underground section of Line-3 is anticipated to open for commercial operations by 2029. This timeline reflects the meticulous planning and execution required to ensure the highest standards of safety and efficiency in metro construction.

Impact on Kolkata’s Transit System

The completion of Kolkata Metro Line-3’s underground section is set to revolutionize the city’s public transport system. The new line will alleviate traffic congestion, reduce travel time, and provide a more sustainable mode of transportation for daily commuters. The strategic location of stations will enhance accessibility and convenience for a large number of passengers.

Conclusion

L&T’s commencement of casting the first tunnel segment for Kolkata Metro Line-3 marks a significant milestone in the city’s metro expansion project. As construction progresses, the project promises to deliver substantial benefits in terms of connectivity, convenience, and sustainability for Kolkata’s residents. The ongoing development underscores the commitment to enhancing urban mobility and infrastructure in one of India’s key metropolitan areas.