Bangalore Metro’s TBM Tunga Makes Breakthrough at Tannery Station

Tunnel Boring Machine S-839 operated by ITD Cementation India last week recorded a “hidden” breakthrough at Tannery Road Station on Bangalore Metro’s 21.386 km Pink Line which will connect Nagawara – Kalena Agrahara through 18 stations.

Nicknamed Tunga, this was TBM S-839’s 1st of 4 breakthroughs and ITD Cem’s 1st of 8 breakthroughs planned for the 73.92 km Bangalore Metro Phase 2 project’s 4.591 km package RT-04 (Tannery Road – North Ramp).

This Herrenknecht mixed-shield EPB machine was launched in June 2021 and traveled 822.99m south from Venkateshpura to Tannery Road to build the northbound tunnel.

It’s currently tunneling through Tannery Road Station’s box and will tunnel another 209.585m towards a dedicated TBM retrieval shaft. As station excavation progresses, workers will dismantle the tunnel rings built by Tunga within the station box.

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

Alignment of ITD Cem’s Package RT-04 – view Bangalore Metro Phase 2 info & route map

Similar “hidden” TBM breakthroughs have been performed by Afcons Infrastructure in Chennai & Kolkata, and more locally at Dairy Circle Station – see details.

Per BMRCL’s June newsletter, TBM Bhadra (S-840) working on the southbound tunnel has completed 742 meters, and has roughly 80 meters to make its hidden breakthrough. Overall, Package RT-04’s progress stands at 24.74% completion (1575/6365m).

With this development, approximately 47.1% of tunneling work for Phase 2 (total scope: 20,855m) has been completed with 8 out of 26 breakthroughs recorded: 3 on Package RT-01 by Afcons, 2 on RT-02 by L&T, 2 on RT-03 by L&T, and 1 on RT-04 by ITD Cementation.

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Global traveler who prefers mass rapid transit

4 Responses to "Bangalore Metro’s TBM Tunga Makes Breakthrough at Tannery Station"

  1. Ashok Kiumar says:

    Hi TMRG,

    With Tunga and Bhadra slated to complete their drives almost 12 to 18 months after the completion of the other TBM’s. Do you think BMRCL might consider using another TBM like Varada which is slated to complete the tunneling in another 6 months to complete a part of Tunga or Bhadra’s drive? Afcons might have to transfer their TBM to ITD in this case.

    Also are any crossover planned near Pottery town station to enable train reversal and begin partial operations. (Provided they have rolling stock etc.)?

    • TMRG says:

      Hi, I’m not sure if a TBM transfer deal is cooking or not. ITD’s RT-04 is apparently the most challenging as far as terrain goes and BMRCL deliberately required min 2 TBMs to be used to keep costs down. They’re in no hurry for that stretch unlike the southern parts which connect up to other lines. Let’s see what happens.

      I haven’t seen this line’s track layout, but we’ll definitely see a staggered launch of operations. We should know more in 2024.

  2. Sandeep Srivastava says:

    Hi TMRG

    Do you know where the depot is going to be for the pink line ? Also what is the status of the same, is it going to be ready for the launch of this line in time ?


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