New Delhi, March 22 The much-awaited tunnel boring machines to build the country's first undersea rail tunnel for the Mumbai-Ahmedabad high-speed bullet train project are on their way and will be delivered at the Jawaharlal Nehru Port Trust in Mumbai on Monday, sources said.
The customized TBM was manufactured by the German company Herrenknecht in its unit based in China.
Officials said that these TBMs are among the largest and most expensive in the country, with a diameter of 13.1 meters, one of the biggest ever to be used in any rail project in India.
Usually, TBMs with cutter heads of 5 or 6 meter diameter are used for urban tunnels used in the MRTS Metro system.
The package C2 of the Mumbai-Ahmedabad High Speed Rail Project, under which the undersea tunnel comes, is being executed by Afcons Infrastructure Ltd. The whole package involves a 20.37 km-long tunnel.
"Of this, 4.8 km has been completed through the New Austrian Tunnelling Method (NATM) in September 2025, while the remaining 15.489 km will be bored through these TBMs (Tunnel Boring Machine). This tunnel will go about 25 to 65 Meters deep from the ground level," an official said.
He added, "The tunnel will be a single tube tunnel to accommodate twin track for both up and down track. Two shafts at Vikhroli, and Sawli at approximate depths of 56 and 39 meters respectively, will facilitate the construction."
Besides, 39 equipment rooms at 37 locations will also be constructed adjoining the tunnel location as part of the package.
Notably, the cutter head of one of the two TBMs was dispatched from China to Mumbai in September 2025, after the issue was flagged during Prime Minister Narendra Modi's interaction with Chinese President Xi Jinping in August 2025.
However, the remaining components, as well as the second TBM, were stuck due to custom clearances.
Sources said that the matter was continuously pursued through diplomatic channels, with the Railways Ministry coordinating closely with the Ministry of External Affairs.
"Finally, we overcame all hurdles, and the consignment will arrive at JNPT tomorrow afternoon," a source in the Railway Ministry said.
He added, "The delay gave us sleepless nights as the bullet train project is the most ambitious and dream project of this government."
India's First Bullet Train Project - the Mumbai - Ahmedabad High Speed Rail corridor, spanning across 508 kilometres, will offer fast connectivity between Maharashtra and Gujarat states in western India.
According to National High Speed Rail Corporation Limited, after starting from Bandra Kurla Complex (BKC) area in Maharashtra, the high-speed train running at a speed of 320 km/h will revolutionize intercity travel in the region and will integrate the economies of Mumbai, Vapi, Surat, Anand, Vadodara & Ahmedabad.
"It will have stops at 10 cities in between, namely Thane, Virar, Boisar, Vapi, Bilimora, Surat, Bharuch, Vadodara, Anand, Ahmedabad and will terminate at Sabarmati," an NHSRCL official said.
"The entire journey will be completed in about 2 hours 7 minutes with limited stops (at Surat, Vadodara and Ahmedabad), which is substantially less than the time taken by conventional trains or road journeys," he added.