The Chennai Metro Rail Limited (CMRL) Phase II Corridor 4 Update

“Introduction
Phase II Corridor 4 Update

The Chennai Metro Rail Limited (CMRL) has initiated trial runs on a 9.1-kilometre elevated route spanning from Poonamallee Bypass to Porur Junction. This segment is part of Corridor 4 under the Phase II development, aiming to link Light House with Poonamallee via Porur.”

“Stretch
The 10-station stretch includes the following stops:

Poonamallee Bypass

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Poonamallee

Mullaithottam

Karayanchavadi

Kumananchavadi

Kattupakkam

Iyyapanthangal

Thellaiyagaram

Porur Bypass

Porur Junction

These stations form part of the 26.1-km Corridor 4 running from Light House to Poonamallee.

Trial Run Schedule and Speeds Achieved
The first trial on this corridor was conducted on March 20, covering a two-kilometre section between Poonamallee and Mullaithottam at 25 km/h. Subsequent trials have steadily expanded to cover the entire 9.1 km. Current test runs reach speeds between 35–40 km/h. Internal assessments have tested trains at up to 80 km/h without complications.

Use of Driverless Technology in the Trial Phase
Though the trains involved are equipped for driverless operation, human operators are temporarily present during trials for manual oversight. Chennai is poised to become the second Indian city after Delhi to roll out fully autonomous metro operations.

The introduction of driverless trains is expected to reduce human error, optimise train frequency, and enhance safety standards. The Poonamallee–Porur link will serve as a model for upcoming sections in the network.

Key Infrastructure and Design Challenges
The viaduct includes the sharpest curve in the Phase II network near Porur, with a radius of 127.55 metres. This complies with safety standards, which require a minimum 120-metre radius for metro curves.

Technical Assessments During the Trial Phase
Testing protocols include checks for:

Braking response and acceleration consistency

Cooling and ventilation systems (air-conditioning)

Geometry and alignment of tracks

Noise output during operation

Vibration control

To reduce vibrations, tracks are fitted with double resilient fasteners. Officials are monitoring all track geometry and acoustic parameters, and will implement corrective actions if passenger comfort is compromised”.

“Testing Coordination from Poonamallee Metro Depot
The Poonamallee Metro Depot has been designated the control centre for trial and commissioning operations. It will handle communication, troubleshooting, and scheduling for all train movements during the testing period.

Number of Trains Involved and Next Steps
Two trains are currently being tested, with two more expected to join the trial process soon. Testing is being conducted on one track for now; the second track will be ready for operations by the first week of June.

Public Operations to Begin Soon
The managing director of CMRL, M.A. Siddique, stated that this trial phase represents a major achievement for the project. It confirms CMRL’s commitment to bringing the Poonamallee–Porur section into operation at the earliest possible date.

Budget and Scope of Phase II
The total cost of Phase II has been estimated at Rs 63,246 crore. Once operational, the Phase II Corridor 4 will improve mobility across western Chennai, reduce dependency on road travel, and help mitigate emissions.

CMRL has announced that future trials will extend beyond Mullaithottam to Porur Junction. Comprehensive inspection of systems and passenger safety checks will be completed before the public rollout later this year.”