
The work is part of Corridor 4, a 26.1 km line from Light House to Poonamallee. The Porur–Power House section includes a 3.75 km double-decker stretch between Alwarthirunagar and Alapakkam, which will connect to the Phase I network at Vadapalani. This link will enable seamless transfers between Corridor 4 and Corridor 5 at Alwarthirunagar, Valasaravakkam, Karambakkam, and Alapakkam.
According to CMRL officials, 95% of the 340 piers in this section have been completed. The project, however, faced a six-month delay due to challenges such as working in congested localities, the need for special launching girders, and the relocation of underground pipelines and cables.
While most of the viaduct is already in place, construction work near Valasaravakkam, Alwarthirunagar, and Vadapalani is expected to be completed within the next two months. Track-laying and installation of overhead equipment (OHE) are progressing at Vadapalani, Saligramam, Karambakkam, and Alapakkam, with completion expected in about four months.
The first level of the double-decker stretch is scheduled to open by mid-2026. The second level will begin operations once a portion of Corridor 5 is ready, promising better connectivity and shorter travel times for commuters across the city.