Kolkata Metro Purple Line Tunnel Breakthrough
RAILWAYS & METRO RAIL

Kolkata Metro Purple Line Tunnel Breakthrough

The tunnel boring machine (TBM) DIVYA has completed a breakthrough at Victoria metro station, marking the end of the drive between Khidderpore and Victoria on the Joka-Esplanade Metro Corridor. The drive covered one point seven two kilometre (km) beneath central Kolkata and advances the construction of the Purple Line. The milestone follows successive tunnelling stages that linked key stretches of the route and prepares the alignment for station fit-outs and system installations.

The tunnel boring machine measured 95 metre (m) in length and weighed around 600 tonne (t) when assembled. Its outer diameter was six point six metre (m) with a finished tunnel diameter of five point eight metre (m). Precast segments specified at grade M50 and thickness 275 millimetre (mm) were used to line the bore, and two TBMs are being deployed to create twin tube tunnels along the corridor.

Key construction works included a launching shaft excavated inside St Thomas School at Khidderpore measuring 37 metre by 22 metre and 17 metre deep, which served as the lowering and assembly site for the machine. The TBM was manufactured in Chennai and mobilised to Kolkata in March 2025 for assembling and lowering, after which it proceeded beneath urban infrastructure. The tunnelling method transitions to conventional cut and cover beyond Park Street where surface conditions allow.

Earth pressure balancing technology was employed to contend with a high ground water table and soft soil strata typical of the city, with safety systems such as an inflatable seal, pressure transducers and dedicated TSG lines plus a backup TSG pump incorporated into the design. Project authorities described the breakthrough as a significant milestone that accelerates work on station completion and systems integration ahead of planned commissioning phases. The progress is expected to enhance connectivity along the Purple Line and support urban transit capacity once services commence.

The tunnel boring machine (TBM) DIVYA has completed a breakthrough at Victoria metro station, marking the end of the drive between Khidderpore and Victoria on the Joka-Esplanade Metro Corridor. The drive covered one point seven two kilometre (km) beneath central Kolkata and advances the construction of the Purple Line. The milestone follows successive tunnelling stages that linked key stretches of the route and prepares the alignment for station fit-outs and system installations. The tunnel boring machine measured 95 metre (m) in length and weighed around 600 tonne (t) when assembled. Its outer diameter was six point six metre (m) with a finished tunnel diameter of five point eight metre (m). Precast segments specified at grade M50 and thickness 275 millimetre (mm) were used to line the bore, and two TBMs are being deployed to create twin tube tunnels along the corridor. Key construction works included a launching shaft excavated inside St Thomas School at Khidderpore measuring 37 metre by 22 metre and 17 metre deep, which served as the lowering and assembly site for the machine. The TBM was manufactured in Chennai and mobilised to Kolkata in March 2025 for assembling and lowering, after which it proceeded beneath urban infrastructure. The tunnelling method transitions to conventional cut and cover beyond Park Street where surface conditions allow. Earth pressure balancing technology was employed to contend with a high ground water table and soft soil strata typical of the city, with safety systems such as an inflatable seal, pressure transducers and dedicated TSG lines plus a backup TSG pump incorporated into the design. Project authorities described the breakthrough as a significant milestone that accelerates work on station completion and systems integration ahead of planned commissioning phases. The progress is expected to enhance connectivity along the Purple Line and support urban transit capacity once services commence.

Related Stories

Gold Stories

Next Story
Real Estate

Anshul Singhal launches Vantrock with Rs 42 billion development plan

Real estate professional Anshul Singhal has launched Vantrock Real Assets Private Limited (VRAPL), a Mumbai-headquartered platform focused initially on warehousing, industrial and logistics parks. The company plans to develop approximately 11.5 million sq ft of assets, with an estimated gross development value (GDV) of Rs 42 billion (approximately USD 434 million) on completion.The first phase will cover around 3 million sq ft across the National Capital Region (NCR), Bengaluru and Pune, with an estimated development value of Rs 11 billion (approximately USD 113 million). Construction is sched..

Next Story
Infrastructure Transport

Afcons wins CII award for biodiversity management

Afcons Infrastructure has received the Confederation of Indian Industry (CII) National Award for Environmental Best Practices 2026 in the Biodiversity Management category for its work on the Mumbai-Ahmedabad High Speed Rail Project’s C-2 package.The award was presented at a ceremony in Chennai on 9 October 2026. It was received by Mihir Mishra, Vice-President, CPE, and Sumon Paul, Assistant General Manager, HSE, along with the Afcons team.The project adopted several resource recovery and waste management practices. These included recycling concrete washout waste to recover sand, aggregates a..

Next Story
Technology

Indian businesses lead globally in planned AI investment, says Autodesk

Indian organisations are moving towards deeper integration of artificial intelligence (AI), digital technologies and sustainability into business operations, according to Autodesk’s 2026 State of Design & Make report. The fourth edition of the annual study highlights growing AI adoption, measurable outcomes from digital transformation and the role of sustainability in long-term business growth.The report found that 64 per cent of Indian organisations are approaching or have achieved their current AI goals. While 88 per cent believe AI will enhance their industry, up from 78 per cent in 2..

Advertisement

Subscribe to Our Newsletter

Get daily newsletters around different themes from Construction world.

STAY CONNECTED

Advertisement

SPECIAL OFFER
QR Code