India must not let this import dependence choke its infrastructure build-up

As we make no large diameter TBMs (10m and above), we remain vulnerable to a Chinese supply squeeze. Recently, China not only halted direct TBM exports to India, but also reportedly blocked subcomponents made in Chinese facilities of a German firm, choking supplies at two levels of the chain.

As a geopolitical lever, TBM holdbacks could delay or derail India’s infrastructure plans. The global TBM industry is highly concentrated, dominated by Germany’s Herrenknecht, America’s Robbins Company, China Railway Engineering Equipment Group, China’s Terratec and Japan’s Hitachi Zosen Corp. Why does India not make TBMs?

First, high-diameter machines demand components of ultra-high-strength steel and abrasion-resistant alloys that withstand extreme pressure. Cutterheads and shields must resist sustained loads and micro-structural fatigue, as any weakness can cause catastrophic failure. While India has advanced in steelmaking and heavy forging, it lacks specialized metallurgy and large-diameter forging expertise.

Second, while our heavy engineering industry has capacity in turbines and boilers, it has not developed gear and bearing technologies needed for TBMs. Third, modern TBMs are cyber-physical systems that integrate geotechnical sensors, servo drives, electro-hydraulic controls and the like, for which we remain import-dependent. Finally, we lack an industrial ecosystem and specialized human capital for TBM production, which requires supplier clusters for cutters, seals, hydraulics, conveyors and erectors.

Moreover, TBM designs evolve through iterative feedback loops across hundreds of tunnelling projects, supported by test infrastructure and specialized training. India does not yet have large-scale tunnelling simulators.

China had similar challenges when it started creating its TBM ecosystem in 1964. Till the 1990s, most of its large tunnelling projects used imported machines, but a policy decision in the early 2000s required major foreign suppliers to set up local assembly and service bases as a condition for supplying metro and hydropower projects.

Training, maintenance and component fabrication began to shift onshore, while state-owned enterprises built their own plants supported by state labs. China indigenized TBM-making in stages. By 2022, it was producing over 200 TBMs annually, covering diameters from 3m to 17m, with localization rates above 90% for critical systems.

India must take six steps to indigenize TBMs, anchored by a targeted incentive scheme. First, launch a scheme that ties incentives to domestic value addition and mandates that global suppliers establish local assembly, machining, and service plants to bag metro, hydropower and highway projects.

Second, ask public sector engineering enterprises to anchor joint ventures with global TBM makers, using metro corporations and highway authorities as demand guarantors.

Third, develop a local component ecosystem by enabling Indian heavy engineering and metallurgical firms to make large bearings, high-torque gearboxes and alloy steels for cutterheads and shields, while progressively indigenizing hydraulics and control electronics through industrial partnerships.

Fourth, enforce national standards to ensure interoperability and quality across the supply chain.

Fifth, establish a Centre of Excellence in Tunnelling Machinery at IITs and IISc, supported by programmes on cutterhead wear, slurry systems and intelligent controls, to create India-specific TBMs adapted to Himalayan geology.

Sixth, deploy financing tools, low-cost credit, bundled EPC (engineering, procurement and construction) contracts and procurement clauses that mandate rising domestic content. This will lower entry barriers for contractors and aid export competitiveness.

This roadmap will get local assembly going and create a supply chain that can cut dependence on foreign suppliers and establish India as a credible TBM hub within a decade. Unless India commits itself to building indigenous TBM capacity, it will remain hostage to foreign suppliers for its ambitious infrastructure build-up.

The author is a public policy professional.