TBM S1073 Makes Final Breakthrough for Mumbai Metro L-3’s UGC-04

Besides the Bombay High Court’s decision to grant interim stay on the Collector’s order to transfer land in Kanjurmarg for a pipe-dream mega-depot, there’s another reason to rejoice today!

Moments ago, Tunnel Boring Machine S-1073 (Krishna-1) operated by the Continental Engineering Corp – ITD Cementation – Tata Projects JV made a breakthrough at Dadar Station’s southern-end on Mumbai Metro’s 33.5 km Aqua Line (Line-3).

This was S-1074’s third (and final) breakthrough, Package UGC-04’s 8th ( and final!) breakthough for the 6.08 km Worli – Dharavi section, and overall Line-3’s 35th of 42 planned breakthroughs.

This Herrenknecht Earth Pressure Balance (EPB) machine passed factory acceptance testing (FAT) in June 2017, and in November became the first of 17 TBMs of Line-3 to be commissioned.

For its first assignment, it built the 2491m up-line tunnel Nayanagar Shaft to Dadar Station. After recording a double breakthrough along with its sister machine S-1074 in January 2019, it was recommissioned again from Nayanagar Shaft to build the 589m up-line tunnel towards Dharavi Station, where it arrived in November 2019.

For its final assignment that ended today – the machine was dismantled and recommissioned from Siddhivinayak Station in February 2020 to build the 1126m down-line tunnel with 798 tunnel rings.

A video of the breakthrough with frenzied scenes of workers dancing can be viewed on my Twitter handle here.

With this development, tunneling works on 4 out of 7 underground civil packages have been wrapped up –

• UGC-02: CST – Mumbai Central (4.049 km) – Final breakthrough recorded by TBM T59 (Vaitarna-2) in April 2020
• UGC-04: Worli – Dharavi (6.08 km) – Final breakthrough recorded by TBM S1073 (Krishna-1) today!
• UGC-05: Dharavi – CSIA T1 (4.94 km) – Final breakthrough recorded by TBM S64 (Godavari-4) in August 2020
• UGC-07: CSIA T2 – Sariput Ramp (4.157 km) – Final breakthrough recorded by TBM D213 (Wainganga-2) in December 2019.

Here’s a table displaying UGC-04’s tunneling plan (best viewed on a desktop device) and the status of each tunnel –

TBM	Line	From	To	Distance	Status
1	Up	Nayanagar Shaft	Dadar	2491m	Completed Jan 31 2019
1	Up	Nayanagar Shaft	Dharavi	589m	Completed Nov 21 2019
1	Down	Siddhivinayak	Dadar	1126m	Completed Today!
2	Down	Nayanagar Shaft	Dadar	2472m	Completed Jan 1 2019
2	Down	Nayanagar Shaft	Dharavi	589m	Completed Oct 11 2019
2	Up	Siddhivinayak	Dadar	1106m	Completed Oct 5 2020
3	Up	Siddhivinayak	Worli	1305m	Completed Mar 15, 2019
3	Down	Siddhivinayak	Worli	1284m	Completed March 16, 2020

With 35 breakthroughs completed, there are now 7 more breakthroughs pending on Mumbai Metro’s Line-3:

Package	Section	Distance, Status
UGC-01	Hutatma Chowk – CST (up-line)	551m, Not Started
UGC-01	Hutatma Chowk – CST (down-line)	556m, Not Started
UGC-03	Science Museum – Mahalaxmi (up-line)	1118m, In Progress
UGC-03	Mahalaxmi – Mumbai Central (up-line)	837m, Not Started
UGC-03	Science Museum – Mahalaxmi (down-line)	1136m, In Progress
UGC-03	Mahalaxmi – Mumbai Central (down-line)	830m, Not Started
UGC-06	Sahar Road – CSIA T1 (up-line)	1516m, In Progress

The final breakthrough on J Kumar – CRTG JV’s Package UGC-06 (Santa Cruz MVS – CSIA T2) is expected to take place towards the end of Q1 2021. When that happens, the line’s twin tunnels will be ready all the way from Science Museum in South Bombay to Sariput Nagar ramp at the mouth of Aarey Colony where the line’s depot was originally planned.

I’m expecting all tunneling works to be completed in Q4 2021 if no major hiccups arise.

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

– TMRG