Bangalore Metro Phase 2’s Final Breakthrough Recorded to Complete Tunneling Works

Historic moment! ITD Cementation India today celebrated tunnel boring machine (TBM) S-840B’s final breakthrough at Nagawara Station’s South Shaft on the 21.386 km Bangalore Metro Pink Line (Reach 6) project.

This major milestone by TBM Bhadra marks the completion of 26 TBM breakthroughs and 100% tunneling works (scope of 20,992m) for the 73.92 km Bangalore Metro Phase 2 project. It was Bhadra’s 4th breakthrough and the 8th breakthrough for the project’s 4.591 km Package RT-04 (Tannery Road – North Ramp).

TBM Bhadra – a Herrenknecht mixed-shield EPB machine was first commissioned from Venkateshpura Station southward to Tannery Road in June 2021. For its latest assignment, it built a roughly 937m tunnel northward from Kadugondanahalli to Nagawara’s Cut & Cover Shaft-1 boring at an average rate of 4.4m/day through mixed face hard rock conditions.

Here’s a summary of all completed drives:

• Venkateshpura to Tannery Road (822m): June 2021 – July 2022
• Tannery Road to Shadi Mahal TBM Retrieval Shaft (222m): July 2022 – December 2022
• Venkateshpura to Kadugondanahalli (1184m): February 2023 – February 2024
• Kadugondanahalli to Nagawara C&C-1 (937m): April 2024 – October 2024

ITD Cem’s scope of work involved building a combined total of 6.34 km twin tunnels, roughly 360 meter ramp at Nagawara, and four underground stations at Tannery Road, Venkateshpura, Kadugundanahalli (formerly Arabic College) and Nagawara.

A cool video of the entire event can be viewed here.

With this development, all 9 TBMs deployed by Phase 2’s 3 contractors have completed their assignments for the Pink Line’s 13.92 km underground section.

The first TBM (Urja) for the project was commissioned by Larsen & Toubro in July 2020 from Cantonment Station, while Bhadra was the last machine to get going in June 2021 and now joins Varada, Avni, Urja, Lavi, Vindhya, Vamika & Rudra, and Tunga in retirement.

Here’s a recap of final breakthroughs recorded for each package:

• Package RT-01 (3.655 km, Afcons Infrastructure): TBM Rudra in October 2023
• Package RT-02 (2.755 km, Larsen & Toubro): TBM Lavi in February 2023
• Package RT-03 (2.844 km, Larsen & Toubro): TBM Vindhya in February 2023
• Package RT-04 (4.591 km, ITD Cementation): TBM Bhadra in October 2024 (this post!)

With this development, the only tunneling works remaining are for 15 cross-passages between parallel tunnels for passenger safety and maintenance purposes. These passages, placed 250-400m apart, are in various stages of completion.

Unlike Phase 1 where delays were incurred on the civil (tunneling) side of things due to poor geotechnical investigation and contractor selection, delays on Phase 2’s underground section will be booked by system procurement delays, more specifically by the unavailability of trains.

The commissioning of the 21.38 km Pink Line and the length of its “Phase 1” entirely depends on how quickly BEML is able to supply train-sets from rolling stock contract 5RS-DM which was awarded only in August 2023. That contract is the long pole and on the critical path as station civil & architectural finishing and systems installation work should be wrapped up on the entire line by 2025-end.

The first of 53 trains from BEML’s local Bengaluru complex in CV Raman Nagar is expected to roll out in Q4 2025 – view design here, so in the best case scenario we’ll see commercial operations begin only in Q3 2026 when BMRCL has a certain number of train-sets in hand, tested and ready to service the line.

Even if RT-04’s four stations are ready by then, I believe there’s a possibility that BMRCL will open these stations at a later stage in order to maintain a respectable frequency on “Phase 1” of the line. What “Phase 1” will look like remains anyone’s guess, but I’d imagine it to include the Kalena Agrahara – Dairy Circle – MG Road section which consists of a mix of elevated (Reach 6 viaduct) and underground sections (RT-01 & RT-02).

Today was a historic day and I’m glad to have been able to record and share all tunneling breakthroughs on my site. Back in 2016-2017, I posted about Phase 1’s tunneling history with details of all breakthroughs recorded by 6 TBMs. Check it out here for Purple Line and here for Green Line.

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– TMRG