TBM S718 Makes a Breakthrough at Chennai Metro’s Central Station

Apologies for the late post – it’s been a little hard to get these images.

On this past Tuesday, Tunnel Boring Machine S718 – a Herrenknecht EPB Tunnel Boring Machine operated by the Afcons-Transtonnelstroy JV for Chennai Metro’s package UAA-01 made a successful breakthrough at Central Station just weeks after S717 arrived here while building the parallel tunnel. The TBM was commissioned from the Egmore Station in March 2016 and traveled roughly 1 km while building 715 rings along the way for the 22 km Chennai Central – St. Thomas Mount line.

This is the 5th of 6 TBM breakthroughs scheduled to take place at Central Station’s TBM receiving shafts. The first breakthrough was achieved in July 2014, 2nd in January 2016, 3rd in October-end and the 4th in mid-November.


Egmore to Central stretch – view Chennai Metro map & info


Waiting for S718 to arrive next to S717 – Photo Copyright: Anish


..and we have a breakthrough! – Photo Copyright: Anish


Photo Copyright: Anish


TBM S718 & S717 – Photo Copyright: Anish


There are now just 3 more TBM breakthroughs left for tunneling to end on Chennai Metro’s 45.1 km Phase 1 project:

Package TBM Origin Destination Approx Pending
UAA-01 S710 High Court Central 145 m
UAA-02 S703 Thousand Lights AG-DMS 1.55 km
UAA-02 S704 Thousand Lights AG-DMS 1.67 km

The contractor (Afcons Infra) is expecting TBM S-710 to arrive at Central Station by February 2017.

TBM S703 has commenced tunneling works towards AG-DMS station for 1 final drive after undergoing maintenance via a small overhaul shaft at the Thousand Lights station. Afcons was initially able to achieve amazing rates of 32m/day, but work has since slowed down due to old equipment & frequent OS failures.

TBM S704 is still undergoing maintenance at Thousand Light station and will restart tunneling in the coming weeks.

For more updates, check out the Chennai section of The Metro Rail Guy!


written by

Global traveler who prefers mass rapid transit

13 Responses to "TBM S718 Makes a Breakthrough at Chennai Metro’s Central Station"

  1. Akhil says:

    No need to apologize. I love your updates even if some are delayed for our benefit or otherwise 🙂

  2. arvind says:

    Good update even if it is late.

    Its amazing to see s703 achieve a rate of 32m/day. Unfortunate that the momentum could not be kept.

    • TMRG says:

      A couple years back L&T achieved roughly 190m in a week between Egmore-Shenoy Nagar on UAA04 – now that was something 😀

  3. Kamal says:

    You provide really good updates, I have a suggestion, give a single monthly update for other metro systems which does not have any big news .

    • TMRG says:

      Hi, thanks for your suggestion. For small news/updates and one-off images, I share them via my Twitter handle as it’s just a lot easier than digging, collecting & compiling them in one single post.

  4. Anand says:

    looks like S710 ll reach Central by Feb
    Wut abt S703/4 – wen we cn expect final break through?

    pls update us on washermanpet wimco ngr extension as well.When we cn expect tunnelling to begin? Also whthr egmore metro wud be open along with central metro?

    Thanks for your timely update!

  5. Pradeep says:

    The newsletter says that the Thirumangalam Egmore stretch is already completed and trials are under way. so can we expect this stretch to open sometime in April 2017? Or will it be just the thirumangalam to shenoy nagar which will be open for commissioning?.

    • TMRG says:

      Hi, operations will commence only between Koyambedu – Shenoy Nagar since the Egmore Station, shaft & tunnels leading to Central station are still in the “construction” stage.

      Btw, here are 2 recent images of one of the entrances to Thirumangalam Station. Thought you might like it 🙂

  6. Subramanian says:


    Nowadays, there is no news about chennai metro rail…we could see news predominantly on delhi metro and other metro’s…Any reason that chennai is being neglected?


    • TMRG says:

      Hi, I’m not neglecting any city. There just isn’t any big update from Chennai, that I’m aware of, for me to write about. This month S710 will make a breakthrough at Central and 1 of 2 TBMs will commence tunneling from Washermentpet to Sir Theagaraya College Station. I will write about those updates as soon as the take place.

      • Subramanian says:

        Thanks for the update…We are in dark as CMRL has stopped publishing the newsletter and no source to know the happenings of Chennai metro..


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