35 months after being commissioned from the North Ramp close to Sampige Road Metro station in Bangalore, the ‘Godavari’ Tunnel Boring Machine (TBM) today finally made a breakthrough at the northern-end of the Majestic station!
The Coastal-TTS JV which is in-charge of building the Green Line’s tunnels (contract UG1) procured this EPMB TBM from Italy’s SELI and started its 973m journey southward towards the Majestic station on May 21 2013. As per the original plan, Godavari was supposed to make a breakthrough at Majestic and then return back to the North Ramp, but the contractor on the onset ran into difficult tunneling conditions. Due to that, the TBM was only able to advance by an abysmal distance of 352m in the first 13 months, and finally gave up & broke down in June 2014, just south of the railway line in the Lakshmanpuri area.
To keep the Phase 1 project on track, the BMRCL prior to this incident appointed UG2’s contractor, the CEC-SOMA-CICI JV, to use TBM Margarita to excavate & build the down-line tunnel which it completed tunneling on November 7 2015 – see details and images here. Over the next year, the Coastal-TTS JV excavated a 60 feet deep shaft to reach Godavari and ordered a new cutterhead from Italy which got fixed onto it in July 2015 (see details & images of the operation). Subsequently, in September 2015, Godavari cautiously restarted tunneling towards Majestic.
Satellite view of Majestic’s northern TBM receiving shaft where the breakthrough was made:
With this breakthrough, the Green Line’s northern leg (Nagasandra – Sampige Road) is now effectively “connected” to the Purple Line at Majestic via the twin tunnels bored by Godavari & Margarita, but it’ll be many more months before train services start, most likely using a single line like done on Delhi’s Violet line between Mandi House & ITO stations.
Now only 2 more breakthroughs by TBM Krishna & TBM Kaveri are left to be made on the Green Line between Chickpete and Majestic. See details of their progress here: Bangalore Metro – April 2016 Tunneling Update.
For more updates, check out the Bangalore section of The Metro Rail Guy!