L&T Casts Kolkata Metro Line-3’s First Tunnel Segment

Larsen & Toubro this week began pouring concrete to cast the first batch of tunnel ring segments for 15.215 km Kolkata Metro Line-3 (Purple Line)’s 5.05 km underground package UG1.

L&T is responsible for constructing Line-3’s only underground section between Mominpur – Esplanade. This section with twin tunnels will consist of 4 underground stations at Kidderpore, Victoria Memorial, Park Street and Esplanade. At Esplanade, Line-3 when opened will form city’s first 3 line interchange with Blue Line (Dakshineswar – Kavi Subhash) and 16.34 km Green Line (Howrah Maidan – Sector V).

L&T’s casting yard for UG1 is located in Sarkarpool neighborhood of Maheshtala near Line-3’s Majerhat Station. From back of the hand calculations, I estimate they’ll churn out at least 4000 segments to build this section’s twin tunnels which will have an inner diameter of 5.8 meters.

L&T was awarded 5.05 km Package UG1’s Rs. 2447 crore civil construction contract by Rail Vikas Nigam Ltd (RVNL) after being declared as its lowest bidder in June 2023.

Out of 5.05 km (chainage 9063.00m to 14113.00m), roughly 500 meters on the line’s northern-end between Esplanade and Park Street will be built using the cut and cover method.

Each reinforced concrete tunnel ring will be 1,400mm wide by 275mm thick, and consist of 5 segments + 1 smaller ‘key’ segment.

L&T had officially commenced construction work on this package, starting from the Victoria Memorial Station site in Maidan, in May 2024.

Metro Rail Kolkata on X has confirmed L&T will be deploying two Herrenknecht tunnel boring machines (TBMs). Preparatory work for construction started in June-end for this package’s TBM launch shaft at St. Thomas School in Kidderpore neighborhood.

I see tunneling work starting no sooner than Q2 2025 and this underground section opening up for commercial operations no sooner than 2029.

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– TMRG