Chennai-Bengaluru High-Speed Rail Corridor Enters Key Design Phase, Nearly 35 km of Tunnels Planned

The proposed Chennai-Bengaluru bullet train corridor has entered a crucial planning stage, with the National High Speed Rail Corporation Ltd (NHSRCL) selecting it among the first high-speed rail projects for detailed structural design and engineering preparation.

The move indicates that groundwork for the ambitious corridor is progressing beyond the conceptual stage. Apart from the Delhi-Agra section of the Delhi-Varanasi high-speed rail project, the Chennai-Bengaluru route has been prioritised for preparing standard designs, design basis reports and detailed engineering drawings - documents that will eventually form the technical foundation for construction tenders.

The high-speed rail corridor is being designed for trains to operate at a commercial speed of 320 kmph, while the supporting infrastructure, including bridges, tunnels and other civil structures, will be built to withstand a design speed of 350 kmph, according to a report in DT Next.

Underground terminals planned in Chennai and Bengaluru

The proposed Chennai terminal will be a major underground facility with six tracks. The station design includes two island platforms and two side platforms, each capable of accommodating 415-metre-long bullet trains.

The terminal will also feature high-speed crossovers, allowing trains to switch tracks at speeds of up to 120 kmph, improving operational efficiency and reducing delays.

On the Bengaluru side, Baiyappanahalli has been identified as the location for the underground terminal station. Similar to Chennai, it will have six lines with the same platform configuration to handle high-speed train operations.

An underground intermediate station is also planned at Whitefield, where all trains operating on the corridor will stop. The station will have two tracks.

Nearly 35 km of tunnels planned

One of the key engineering challenges of the Chennai-Bengaluru high-speed rail corridor will be its extensive underground sections.

The project includes a 3.87-km tunnel connecting the Chennai terminal, a 15.92-km tunnel approaching the Bengaluru terminal and a 14.79-km mountain tunnel passing through the Kaundinya Wildlife Sanctuary.

Together, these sections account for nearly 35 km of tunnelling work.

The corridor is expected to cover around 306 km in its initial Chennai-Bengaluru stretch and forms part of the larger 463-km Chennai-Bengaluru-Mysuru high-speed rail project.

Designs to follow global practices with Indian standards

NHSRCL plans to use lessons from the ongoing Mumbai-Ahmedabad bullet train project to create standardised designs for future high-speed rail corridors in India.

The appointed consultant will study international high-speed rail systems in countries such as Japan, China, European nations and the United States before recommending design standards suitable for Indian conditions.

While operational requirements such as speed, passenger comfort, vibration control and safety will follow global high-speed rail benchmarks, structural designs will primarily be based on Indian engineering codes, with modifications wherever required.

The standardisation approach is aimed at reducing design timelines and speeding up construction. Instead of preparing separate designs for every construction package, contractors will be able to adapt approved standard designs according to local site conditions.

Wide range of structures covered under consultancy

The design consultancy will cover several major components of the corridor, including underground stations, tunnels, ventilation shafts, emergency exits, cut-and-cover structures, drainage systems and waterproofing arrangements.

It will also include detailed engineering for:

• Viaducts and river bridges
• Steel bridges and special structures
• Station buildings and approach viaducts
• Depot approach lines
• Maintenance facilities
• Bridge bearings and expansion joints
• Noise barriers
• Derailment containment systems

The designs will have to comply with strict international requirements related to passenger safety, structural stability, vibration control and long-term operational reliability.

Part of India's High-Speed Rail expansion plan

The Chennai-Bengaluru corridor is among the priority routes identified under India's proposed high-speed rail expansion programme, often referred to as the "High-Speed Diamond" network.

Earlier, Union Railway Minister Ashwini Vaishnaw said the southern high-speed rail network would transform connectivity between major economic centres, with the Chennai-Bengaluru journey expected to be reduced to around 73 minutes.

The project is being developed by Indian Railways in coordination with National High Speed Rail Corporation Limited and is expected to play a key role in connecting major urban and industrial hubs in southern India.

Once completed, the Chennai-Bengaluru-Mysuru high-speed rail corridor will mark a significant expansion of India's bullet train network beyond the Mumbai-Ahmedabad project currently under construction.