Mumbai-Ahmedabad Bullet Train Project: Indian Railways achieves second mountain tunnel breakthrough in Palghar
On February 3, 2026, National High Speed Rail Corporation Limited (NHSRCL) achieved a breakthrough in the second mountain tunnel (MT-6) on the Mumbai-Ahmedabad High Speed Rail (MAHSR) corridor.
MT-6 is 454 metres long and 14.4 metres wide; it was excavated from both ends using the New Austrian Tunnelling Method (NATM) and completed within 12 months.
The first mountain tunnel breakthrough (MT-5, at Saphale) was achieved on January 2, 2026.
Seven mountain tunnels are under construction in Palghar district (Maharashtra); two have now achieved breakthroughs, with the remaining targeted for completion by August 2026.
The project's critical challenge: the 7-km undersea tunnel under Thane Creek (the world's first undersea high-speed rail tunnel) awaits Tunnel Boring Machines (TBMs) — over 60% of parts for the first TBM have arrived from China, but two other TBMs remain stuck at Chinese ports.
Over 300 km of elevated viaduct structures have been completed as of June 2025; an initial section between Surat and Bilimora (Gujarat) is planned to open on August 15, 2027.
Mumbai-Ahmedabad High Speed Rail Corridor — Project Overview and Strategic Significance
The Mumbai-Ahmedabad High Speed Rail (MAHSR) corridor, popularly called the bullet train project, is India's first high-speed rail line. Spanning 508.17 km between Bandra Kurla Complex (BKC) in Mumbai and Sabarmati in Ahmedabad, it will reduce travel time from approximately 7 hours (current fastest train) to about 2 hours at an operating speed of 320 kmph. It is India's largest transportation infrastructure project, estimated to cost approximately ₹1.08 lakh crore. The project is being executed by NHSRCL (incorporated February 2016) — a joint venture between the Government of India and the Government of Gujarat and Maharashtra.
Key Details
- Total corridor length: 508.17 km (12 km underground in Maharashtra; 496 km elevated)
- Operating speed: 320 kmph; maximum design speed: 350 kmph
- Number of stations: 12 (8 in Gujarat, 4 in Maharashtra including BKC)
- Total project cost: approximately ₹1.08 lakh crore (revised from earlier estimate of ~₹97,636 crore)
- Funding structure: 81% from JICA (Japan International Cooperation Agency) as 50-year ODA loan at 0.1% interest; 10% GOI; 9% State governments
- Train sets: NHSRCL released tender for 24 E5-Series Shinkansen trainsets at approximately ₹11,000 crore
- Target: Surat-Bilimora section: August 15, 2027; Full corridor: December 2029
The second mountain tunnel breakthrough marks progress on the technically challenging Maharashtra section — the 7 tunnels in Palghar (some through difficult rocky terrain, some under densely built areas) are among the most complex elements of the entire project.
Japan's Shinkansen Technology and India-Japan Infrastructure Partnership
The MAHSR project uses Japan's iconic Shinkansen (bullet train) technology — specifically the E5 Series trainsets operated by Central Japan Railway Company (JR Central). The Shinkansen system, operational since 1964, has a perfect safety record of zero passenger fatalities in over 60 years. The technology transfer arrangements aim to build domestic capabilities in high-speed rail design, signalling, and rolling stock — aligned with Make in India. Japan is financing 81% of the project through JICA at near-zero interest rates (0.1% over 50 years) — the most concessional ODA loan India has received, reflecting the strategic depth of India-Japan relations.
Key Details
- Shinkansen introduced: October 1, 1964 (Tokyo Olympics year); currently serves 9 lines across Japan
- Zero passenger fatalities in 60+ years of Shinkansen operation — world's best safety record
- JICA ODA loan: 50-year tenure, 0.1% interest rate, 15-year grace period — among the most concessional large infrastructure loans globally
- Technology transfer: Japan providing Shinkansen core technologies (signalling, safety systems, track design); Indian firms involved in civil works
- India-Japan Annual Summit: MAHSR is a flagship project reaffirmed at every summit
- Japanese firm JE (Japan East Railway subsidiary) appointed for core Shinkansen technology oversight
The mountain tunnel progress, using NATM (an Austrian tunnelling method adapted globally), demonstrates NHSRCL's growing capability to handle complex underground civil works — a prerequisite for eventually tackling the more technically demanding undersea tunnel.
High-Speed Rail as Infrastructure and Economic Development Tool
High-speed rail (HSR) generates economic benefits beyond travel time savings. International evidence from China's HSR network (the world's largest at 45,000+ km) and Japan's Shinkansen shows that HSR catalyses real estate development around stations, facilitates labour market integration between cities, boosts tourism, and reduces aviation congestion on high-density corridors. The Mumbai-Ahmedabad corridor — connecting India's financial capital with its third-largest commercial hub — traverses one of India's highest GDP-density corridors through Surat, Vadodara, and Ahmedabad. The 12 planned stations are being positioned as transit-oriented development hubs.
Key Details
- China's HSR network: 45,000+ km (world's largest); built in ~15 years with massive state investment
- PM GatiShakti: the national master plan for multimodal connectivity under which MAHSR is positioned alongside freight corridors, highways, and ports
- Dedicated Freight Corridors (DFCs): Eastern and Western DFCs (built separately from MAHSR) free up existing rail network for passenger trains once freight moves to DFCs
- New Austrian Tunnelling Method (NATM): flexible tunnel excavation method using sprayed concrete (shotcrete) and systematic monitoring — suited to variable geological conditions like those in Palghar
- TBM (Tunnel Boring Machine): used for the BKC-Shilphata underground section (21 km in Mumbai) and the 7-km undersea tunnel; delayed arrival of Chinese-manufactured TBMs remains a project risk
The breakthrough in the second mountain tunnel is a physical milestone that demonstrates on-the-ground progress after years of land acquisition delays in Maharashtra — signalling that the infrastructure execution phase is now firmly underway.
- Second mountain tunnel (MT-6): 454 metres long, 14.4 metres wide; breakthrough February 3, 2026
- First mountain tunnel (MT-5, Saphale): breakthrough January 2, 2026
- Tunnelling method: NATM (New Austrian Tunnelling Method)
- Total mountain tunnels in Palghar: 7; 2 completed; remaining targeted by August 2026
- Undersea tunnel (Thane Creek): 7 km; world's first for high-speed rail; TBM components arriving from China
- Total corridor: 508.17 km; 12 km underground, ~496 km elevated
- Operating speed: 320 kmph; travel time Mumbai-Ahmedabad: ~2 hours (current: ~7 hours)
- Project cost: ~₹1.08 lakh crore
- JICA financing: 81% at 0.1% interest over 50 years
- Train sets: 24 E5-Series Shinkansen; tender ~₹11,000 crore
- Viaduct completed: 300+ km (as of June 2025)
- Partial opening: Surat-Bilimora section, targeted August 15, 2027
- Full corridor opening: targeted December 2029
- NHSRCL incorporated: February 12, 2016