L&T’s Kolkata Metro TBM Durga Starts Line-3’s Tunneling Work

Larsen & Toubro (L&T) on Thursday officially commissioned their first tunnel boring machine (TBM) at Kidderpore for constructing 15.215 km Kolkata Metro Line-3 (Purple Line) which will connect Joka – Esplanade via 12 stations.

TBM Durga (S-1410A) is a Ø6.6m earth pressure balance (EPB) machine by Herrenknecht and had passed factory acceptance tests in January 2025 at their facility located in Alinjivakkam, Tamil Nadu.

TBM S-1410A, along with TBM S-1411A (Divya) in the future, will first build twin 1723m tunnels from Kidderpore Launching Shaft at St Thomas School towards Victoria Station as part of Line-3’s 5.05 km underground package UG1 connecting Mominpur – Esplanade.

Here are some snaps from the launch shaft (view satellite imagery on Google Maps):

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. Yuksel Proje – Tumas JV has been engaged by RVNL as the project’s General Consultant (GC) since 2021.

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.

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 Line-1/Blue Line (Dakshineswar – Kavi Subhash) and 16.34 km Line-2/Green Line (Howrah Maidan – Sector V).

A cool video of the TBM’s cutterhead spinning within the launch shaft can be viewed here on X.

L&T in July 2024 had started casting tunnel ring segments in Maheshtala near Line-3’s Majerhat Station. From back of the hand calculations, I estimate they’ll churn out at least 4000 segments to feed both TBMs and build this section’s twin tunnels which will have an inner diameter of 5.8 meters. At this time, I see this underground section opening up for commercial operations no sooner than 2029.

For more updates, check out the Kolkata Metro section or my Home Page! Sign up for free instant email notifications on new posts over here. Like this post? Get early-access to updates and support the site over here.

– TMRG