3 min readJun 14, 2026 11:09 AM IST
First published on: Jun 13, 2026 at 07:37 PM IST
Mumbai-Ahmedabad bullet train project latest update: The National High-Speed Rail Corporation Limited (NHSRCL) is working in full swing on the country’s first bullet train corridor, which will connect Mumbai and Ahmedabad. The 508-km-long High-Speed Rail (HSR) corridor passes through Maharashtra, Gujarat and Dadra & Nagar Haveli.
As part of the Mumbai-Ahmedabad HSR Project, the NHSRCL is now installing ‘tunnel hoods’ at the portals of mountain tunnels. “This is the first time such tunnel hood technology has been designed and implemented for railway tunnels in Bharat.
The Mumbai–Ahmedabad Bullet Train corridor traverses challenging terrain and includes seven mountain tunnels in Maharashtra, and one mountain tunnel in Gujarat. Tunnel hoods are being provided at both ends of these mountain tunnels. ” it said.
First time in India: Mumbai-Ahmedabad bullet train gets Tunnel Hood technology (Image: NHSRCL)
Why tunnel hoods are being installed in the Mumbai-Ahmedabad bullet train project
As tunnel hood technology is being introduced in India for the first time, it is quite interesting to know about what these structures are and how it works. According to NHSRCL, the tunnel hoods are designed to mitigate the tunnel boom effect caused by pressure waves generated by high-speed trains. It is an advanced engineering solution adopted to ensure smoother train operations and enhanced passenger comfort.
🚇 Tunnel-wise Hood & Window Data 8 Tunnels
| Sr. |
Mountain Tunnel |
Tunnel Length |
Hood Length |
Windows |
| 1 |
MT-8Valsad |
350 m |
31 m each side |
20 each end |
| 2 |
MT-7Palghar |
417 m |
32 m each side |
20 each end |
| 3 |
MT-6Palghar |
454 m |
32 m each side |
20 each end |
| 4 |
MT-5Palghar |
1.5 km |
40 m each side |
24 each end |
| 5–6 |
MT-4 + MT-3Palghar LONGEST COMBINED |
2.66 km |
45 m each side |
26 each end |
| 7 |
MT-2Palghar SHORTEST |
228 m |
30 m each side |
20 each end |
| 8 |
MT-1Palghar |
820 m |
35 m each side |
22 each end |
7 of 8 tunnels are located in Palghar district. MT-8 is the only tunnel in Valsad. Longer tunnels have wider hoods and more windows.
Why does the Mumbai-Ahmedabad bullet train need tunnel hood technology?
NHSRCL said that when a high-speed train enters a tunnel, it pushes a large volume of air ahead of it, similar to a piston moving inside a cylinder. “This sudden compression of air generates pressure waves that travel through the tunnel. If not properly managed, these pressure waves can create booming noise, when train exists the tunnel,” it noted.
Thus, the tunnel hoods act as a transition zone between the open environment and the confined tunnel space. By allowing air to enter and exit more gradually, they help control pressure changes and improve the overall aerodynamic performance of the system.
The tunnel hoods on the Bullet Train corridor are designed to:
- Minimise tunnel boom and noise generated by high-speed train movement while exiting
- Lower disturbance to surrounding communities.
- Support safe and efficient operation of trains travelling at very high speeds.
🌬️ Part 1: Special Pressure-Relief Openings
One of the distinctive features of these tunnel hoods is carefully designed pressure-relief vents or windows built into the structure.
Train enters tunnel
→
Air compresses rapidly
→
Vents release pressure
→
Smoother airflow
-
1
Windows allow compressed air to escape gradually into the atmosphere as a train enters the tunnel
-
2
Reduces the intensity of pressure waves that build up ahead of a moving train
-
3
Minimises tunnel boom — the loud sonic effect heard when trains exit tunnels at speed
-
4
Helps maintain smoother airflow throughout the tunnel length
🌍 Part 2: Bringing Global Technology to Bharat
-
✓
Tunnel hoods are a standard feature on high-speed rail systems across the world
-
✓
Widely used in countries operating bullet trains at speeds exceeding 300 kmph
-
✓
India is now adopting this proven global technology for its next-generation rail infrastructure
⚡ Bullet train benchmark speed: 300+ kmph
“In simple terms, the tunnel hood helps the train and the air adjust to each other gradually rather than abruptly, making high-speed rail travel quieter, smoother and more comfortable,” the NHSRCL said.
What happens when a bullet train enters a tunnel? (Image: NHSRCL/enhanced with AI)
Mumbai-Ahmedabad bullet train project gets India's first Tunnel Hood technology (Image: NHSRCL) 
First time in India: Mumbai-Ahmedabad bullet train gets Tunnel Hood technology (Image: NHSRCL)
What happens when a bullet train enters a tunnel? (Image: NHSRCL/enhanced with AI)
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