Contractor Afcons Infrastructure will use the new 7.51m-diameter TBMs for Package 8 ‘Brahampuri down-ramp to Begumpul up-ramp’ section of the Delhi-Meerut Regional Rapid Transit System Project (Delhi-Meerut RRTS). The package comprises a 7.12km tunnel and three underground stations.

Having passed their factory acceptance tests at Terratec’s facility, the TBMs will now be transported to India where they will be reassembled on site and launched in early 2022. Starting from Bhaisali station, the machines will bore different alignments through a geology of sand, silt and clay, passing beneath dense urban areas. One of the TBMs will then navigate an extreme right radius towards Begampul station.

To tackle the expected geology, the contractor specified dome-type cutterheads which, for added versatility, have been designed to allow cutting tools to be exchanged for 17in (432mm) disc cutters; this will allow the TBMs to bore through diaphragm walls and cope with unexpected obstacles, such as old wells or foundations.

As the TBMs progress, they will install 300mm x 1,500mm reinforced concrete universal-style, pre-cast lining rings comprising six segments plus key. Muck removal, segment transport and logistics supply will be via rolling stock using five 45t battery locomotives (also supplied by Terratec).

In contrast to a typical metro system, the Delhi-Meerut RRTS will cater for those looking to travel longer distances at higher speeds and with fewer stops. Currently under construction, the 82.15km-long, semi-high-speed rail corridor is anticipated to be operational by 2025 and will see maximum speeds of 180km/h, allowing the distance between Delhi and Meerut to be covered in less than 60 minutes.