Mumbai Metro’s TBM Tansa-2 Records Breakthrough at Mahalaxmi

Tunnel Boring Machine 1239 operated by Doğuş-Soma JV on Wednesday afternoon arrived at Mahalaxmi Station on Mumbai Metro’s upcoming 33.5 km Line-3 (Aqua Line).

Nicknamed Tansa 2, this was TBM 1239’s 3rd (and penultimate) breakthrough, and Doğuş-Soma JV’s 3rd of 6 breakthoughs planned for package UGC-03 (Worli – Mumbai Central)’s tunnels. Overall, this was Line-3’s 39th of 42 planned TBM breakthroughs.

This Ø6.65m Robbins slurry machine had previously achieved a breakthrough at Worli Station in March 2020 and was then transported back to Science Museum Station through the city’s streets in September.

For its most recent assignment, it was recommissioned in November 2020 for its second drive to build the 1118m up-line tunnel towards Mahalaxmi Station.

Along the way, it passed by its sister machine 1238 (Tansa 1) which was recommissioned a couple months prior in September. Details are a little sketchy, but I hear it suffered a breakdown with damage to the machine’s hydraulic cylinder seals that left the machine immobile for more than a month in the February-March timeframe.

Line-3 has just 2 TBMs working from an all time high of 17. A total of 39 breakthroughs have been recorded so far with 3 more pending – all on Package UGC-03.

Here’s a table displaying UGC-03’s tunneling plan and status of each tunnel (best viewed on a desktop device). Note that TBM 1238 (Tansa-1) and 1239 (Tansa-2) had switched positions (up-line to down-line and down-line to up-line) for their 2nd assignment.

TBM	Line	From	To	Distance	Status
1	Up	Science Museum	Worli	2072m	Completed Jan 2020
1	Down	Science Museum	Mahalaxmi	1136m	In Progress
1	Down	Mahalaxmi	Mumbai Central	830m	Pending Start
2	Down	Science Museum	Worli	2057m	Completed March 2020
2	Up	Science Museum	Mahalaxmi	1118m	Completed July 2021 (this post!)
2	Up	Mahalaxmi	Mumbai Central	837m	Pending Start

The line’s depot is still in limbo with no visible movement in the litigation status of the site identified in Kanjurmarg for a mega-depot or in the tendering front relating to lines 3 & 6’s design and integration consultancy works.

From here on, TBM 1239 will now be dragged across Mahalaxmi Station’s platform level and recommissioned towards Mumbai Central for its final 837 meter journey. I’m trying ascertain 1238’s status and will update this section when I hear something.

For more updates, check out the Mumbai Metro section or my Home Page!

– TMRG