# India’s 1st Bullet Train: Undersea Tunnel Breakthrough Achieved, Mumbai-Ahmedabad in 2 Hours
**Posted on September 20, 2025**
Imagine zipping from the bustling streets of Mumbai to the vibrant vibes of Ahmedabad in just two hours—faster than a quick flight without the airport hassle. That's the promise of India's first bullet train, the Mumbai-Ahmedabad High-Speed Rail (MAHSR) corridor. And today, the project hit a game-changing milestone: a breakthrough in the challenging undersea tunnel beneath Thane Creek. This engineering feat isn't just about digging deep; it's a leap toward revolutionizing travel in the world's most populous nation. Let's dive into the details.
## The Milestone: Breaking Through the Depths of Thane Creek
In a ceremony marked by cheers and controlled blasts, Union Railway Minister Ashwini Vaishnaw triggered the final breakthrough for a 4.88 km stretch of the undersea tunnel using the New Austrian Tunnelling Method (NATM). Tunneling kicked off in May 2024 from three faces, with the first key connection—a 2.7 km section between the Adit (ADIT) and Savali shaft—achieved on July 9, 2025. Today's completion links the Savali shaft to the Shillphata tunnel portal, seamlessly connecting to the project's elevated viaduct.
This 5 km NATM section is a critical piece of the 21 km underground/undersea tunnel from Mumbai's Bandra-Kurla Complex (BKC) station to Shillphata in Thane district. Of that, 7 km plunges beneath Thane Creek—a mangrove-rich estuary teeming with wildlife that couldn't be disrupted by a surface bridge. Safety was paramount: Ground settlement markers, piezometers, and restricted access ensured no harm to nearby structures or ecosystems, while fresh air pumps kept workers breathing easy in the depths.
Vaishnaw, shaking hands with flag-waving engineers, hailed it as "an important milestone," emphasizing how this paves the way for trains to hit 250 km/h in the tunnel itself—faster than many under-river metros worldwide. With 16 km more to go via Tunnel Boring Machines (TBMs), the full undersea link is on track for integration by 2028.
## The Bullet Train Project: A High-Speed Dream Taking Shape
Launched in 2017 as a flagship "Make in India" initiative, the MAHSR spans 508 km across Maharashtra and Gujarat, slashing the current 7+ hour train journey (or 5-hour drive) to a blistering 2 hours and 7 minutes at max speeds of 320 km/h. Funded at ₹1.08 lakh crore (about $13 billion), it's a Japan-India collab, importing Shinkansen tech while building local expertise.
Here's a quick snapshot of the corridor's specs:
| Aspect | Details |
|-------------------------|----------------------------------------------|
| **Total Length** | 508 km (332 miles) |
| **Stations** | 12 (e.g., Mumbai BKC, Thane, Surat, Ahmedabad, Sabarmati) |
| **Trainsets** | 24 air-conditioned Shinkansen-style sets |
| **Top Speed** | 320 km/h (operational); 250 km/h in tunnel |
| **Travel Time** | Mumbai to Ahmedabad: 2 hours 7 minutes |
| **Key Features** | Twin tracks in single-tube tunnels (13.1m diameter, M70-grade concrete), earthquake-resistant design, no pre-booking needed (walk-up in 10 mins) |
Progress is roaring: Over 320 km of viaducts, 300+ km of piers, multiple river bridges (like over NH-48 in Gujarat), and station superstructures in Gujarat are done or advanced. The Sabarmati terminal is nearly ready, and Mumbai's underground BKC station has base slab casting underway. Full operations? Targeted for 2028-2030, with the tunnel opening that year.
## Tech and Engineering: Taming the Sea for Speed
What makes this undersea tunnel a world-beater? It's India's first rail venture beneath seawater, engineered for extremes. The NATM—flexible, rock-supportive drilling—handled the creek's soft sediments and high pressures, while upcoming TBMs will chew through the rest. The single-tube design with parallel tracks allows bidirectional bullet trains to whoosh past at 250 km/h, ventilated for eco-friendliness and lit for passenger comfort.
Challenges? Plenty. Mangrove preservation ruled out bridges, so the tunnel dips underground from BKC for 21 km before surfacing. Geotech surveys mapped every inch, and Japanese know-how ensured seismic resilience in quake-prone zones. Cost overruns and land hurdles delayed starts, but with 70% civil works progressing, momentum is unstoppable.
## Why It Matters: Faster Commutes, Bigger Economies
This isn't just a train; it's a connectivity catalyst. Mumbai and Ahmedabad, economic powerhouses, will forge tighter ties—think seamless business hops, tourism booms, and reduced road congestion (hello, fewer NH-48 jams). The corridor could spawn townships along the route, creating jobs and cutting emissions (electric trains = greener rides).
Vaishnaw envisions a future without reservations: Show up, board in minutes, arrive refreshed. For the 1.4 billion Indians, it's a symbol of self-reliance—blending imported tech with homegrown grit to join the global high-speed club (Japan, China, Europe).
## The Road Ahead: From Tunnel to Tracks
With the breakthrough, focus shifts to lining the tunnel, electrifying tracks, and testing. Next up: Completing the 16 km TBM sections and linking to Gujarat's viaducts. Delays from COVID and clearances are history; now, it's full steam ahead.
India's bullet train era is dawning—faster, smarter, bolder. Will you be first in line for that 2-hour sprint? Share your thoughts below: Excited for the ride, or got questions on the tech?
*Disclaimer: This post draws from official updates; timelines may evolve. Follow NHSRCL for the latest.*
