TERRATEC has completed factory acceptance testing on the first two of four earth pressure balance tunnel boring machines (TBMs) planned for use on the Indore Metro Yellow Line.
The line is a key section of the new rapid transit network in Madhya Pradesh, India.
The TBMs, each with a diameter of 6.61m, were manufactured and refurbished at TERRATEC’s facility in Thailand.
The first pair of machines is being shipped to India for deployment on the project, with tunnelling work scheduled to commence later in 2026. The remaining two machines, comprising one new build and one refurbish, will follow at a subsequent stage.
The entire TBM fleet for Indore Metro Yellow Line includes two newly built units and two refurbished machines, delivered as part of an order procured by the joint venture of Hindustan Construction Company and Tata Projects Limited (HCC–TPL JV). This joint venture is responsible for executing the underground works, known as Package IN-05R, on behalf of the client, Madhya Pradesh Metro Rail Corporation Limited (MPMRCL).
Package IN-05R represents the first underground tunnel segment of the 31.32km Indore Metro Phase 1 development. The contract involves 11.32km of twin tunnels, providing a direct link from a ramp located east of Indore Railway Station to a ramp west of Devi Ahilya Bai Holkar International Airport.
The route will pass through seven underground stations, which are Indore Railway Station, Rajwada, Chota Ganpati, Bada Ganpati, Ramchandra Nagar, BSF/Kalani Nagar, and the Airport.
According to TERRATEC, the first two TBMs will be launched from the Airport station shaft to commence excavation on the early sections of the tunnel alignment. Launch arrangements for the other two machines are yet to be determined.
The geological conditions along the alignment are complex, running beneath central Indore through the Deccan Traps, which are dominated by extrusive igneous (basalt) rock. This material is described as highly to moderately weathered in upper layers, improving in competence with depth.
The route transects hilly terrain on the Malwa Plateau and extends into formations belonging to the Vindhyan Supergroup in certain areas. To manage these variable ground conditions, all four TBMs will be equipped with mixed-ground cutterheads and active earth pressure balance technology, designed to allow steady progress beneath the city’s dense urban corridor.
TERRATEC highlighted that the decision to supply a combination of new and refurbished TBMs for the project is intended to address both delivery schedules and sustainability considerations.
The company’s rebuild programme returns used TBMs to as-new operating condition, aiming to reduce the carbon footprint and capital expenditure associated with procuring newly manufactured machines while supporting timely execution of tunnel contracts.
TERRATEC stated: “This deployment further reinforces TERRATEC’s leadership in the Indian tunnelling market, building on successful projects in Delhi, Lucknow, Pune, Chennai and Mumbai.
“As a leading manufacturer of Tunnel Boring Machines, Raise Boring Machines and Microtunnelling Systems, TERRATEC continues to deliver tailor-made tunnelling solutions backed by prompt onsite assistance, readily available spares and specialised technical support.”
Once completed, the Indore Metro Yellow Line’s underground section is intended to serve as a central link between Indore Railway Station and Devi Ahilya Bai Holkar International Airport, via the city centre. The line is intended to decrease road congestion in central Indore, shorten journey times for rail and air passengers, and introduce an alternative mass transit solution for one of the region’s largest urban areas.
In a separate announcement in April 2026, TERRATEC reported that one of its earth pressure balance machines has also been selected for the Palermo Metro in southern Italy.
For the Politeama–Notarbartolo Lotto II contract, the new 8.18m diameter TBM will excavate 817m of tunnel through Palermo’s city centre. The machine, fitted with 12 electric motors providing a total cutterhead power of 1,320kW, is expected to navigate a 180m radius curve before breaking through at the Politeama Theatre.
