The formal inauguration of the underground tunnel boring work for India's first bullet train project, connecting Mumbai and Ahmedabad, was postponed by the Railway Ministry due to severe rainfall in Mumbai. Despite the delay in the official launch, authorities have been directed to commence operations immediately to maintain the project's timeline.
Heavy rains have been impacting Mumbai, prompting the India Meteorological Department (IMD) to issue 'red' and 'orange' alerts for the coming days. A senior official confirmed that while the Railway Minister's formal launch event was deferred due to these adverse weather conditions, the National High Speed Rail Corporation Limited (NHSRCL) was instructed to proceed without delay.
Crucial Tunneling Underway
Afcons Infrastructure Limited, the contractor responsible for the underground segment, has begun operations with its specialized Tunnel Boring Machines (TBMs). This marks the maiden use of TBM technology for the Mumbai-Ahmedabad High-Speed Rail Corridor.
The project involves constructing a 20.37-kilometer underground tunnel, which includes a significant 7-kilometer undersea stretch. The tunnel will be situated approximately 65 meters below ground level. Two customized German-made TBMs, imported from China in March 2026, are central to this effort. Afcons owns these machines.
Advanced TBM Technology Deployed
The first TBM will excavate a 5.8-kilometer section from Vikhroli to the Bandra Kurla Complex (BKC) station. The second machine, currently being assembled at Sawli, is expected to be operational within a week and will bore the 9.7-kilometer stretch from Sawli to Vikhroli, encompassing the undersea portion.
Each TBM is designed to excavate approximately 300 meters per month. Once both machines are fully operational, the total tunneling progress is anticipated to reach about 600 meters monthly. These TBMs, with cutter-head diameters of 13.6 meters, are among the largest and most expensive heavy machinery deployed for railway projects in India, significantly larger than the 5-6 meter diameter TBMs typically used in urban metro constructions.
The 20.37-kilometer tunnel extends from BKC station to Shilphata. Of this, 15.4 kilometers between BKC and Sawli will be excavated by TBMs, while the remaining 4.8 kilometers from Sawli to Shilphata has already been completed using the drill-and-blast method. The tunnel will feature a single tube accommodating twin tracks for bi-directional train movement. Construction support includes two shafts at Vikhroli and Sawli, at depths of about 56 meters and 39 meters respectively. The package also includes 39 equipment rooms at 37 locations adjacent to the tunnel.
The 508-kilometer Mumbai-Ahmedabad High-Speed Rail Corridor is India's inaugural bullet train project, designed to provide high-speed rail connectivity between the states of Maharashtra and Gujarat.