CHENNAI: A fully constructed arm of the Perungalathur railway overbridge (ROB) connecting Sadanandapuram and Nedunkundram lies unused, with its opening blocked by the widening of a narrow approach road linked to the Tambaram Eastern Bypass project and pending forest-land clearance.

The situation has left motorists confused and residents frustrated. With barricades removed at Nedunkundram, motorists unfamiliar with the route are entering the completed ROB arm, only to find the road closed at the other end and being forced to turn back.

Residents say the completed arm should be opened immediately after addressing the narrow stretch where it descends and joins Nedunkundram Road at Sadanandapuram. They allege that the Highways department is unnecessarily linking the ROB to the Tambaram Eastern Bypass, thus delaying the opening of the structure, which has been completed.

However, a Highways official said that once the arm is open for public use without fully widening the existing road, the traffic flow would increase and result in congestion.

The Perungalathur ROB, conceived in 2000 to ease severe congestion on GST Road, has taken 26 years to reach its present stage. The project was initially estimated at Rs 86 crore, but land acquisition issues and delays involving revenue authorities stalled it.

After the project was revised in 2018 at an estimated cost of Rs 235 crore, work resumed in 2021. The ROB was planned as an oval-shaped structure connecting Perungalathur, Peerkankaranai, Sadanandapuram, Nedunkundram, Vandalur and Tambaram.

Three phases have since been opened to traffic.

The first phase, connecting Vandalur and Peerkankaranai on the Chengalpattu-Tambaram route, was opened in September 2022. The second phase, crossing the railway tracks and connecting Srinivasa Nagar and Perungalathur with Kamaraj High Road, was opened in June 2023. The third phase, on the Tambaram-Chengalpattu carriageway, was opened on August 1, 2024.

The eastern arm towards Sadanandapuram and Nedunkundram was delayed by forest-land issues and the relocation of the Perungalathur TNEB substation. The substation was shifted to Netaji Nagar in New Perungalathur, and the Highways Department subsequently secured 0.9 hectares of forest land for the road connection.

A fresh tender worth Rs 27 crore for the eastern arm was then floated and work began in August 2025. The work is now complete.

However, officials said that the opening the arm immediately could create another traffic bottleneck. "The ROB descends and joins Nedunkundram Road at Sadanandapuram, where the existing road is narrow. Widening this stretch is necessary to prevent severe congestion during peak hours and reduce the risk of accidents," an official told DT Next.

The widening has, however, become linked to the Tambaram Eastern Bypass project, which is a separate project.

The bypass requires 4.46 hectares of forest land. The Centre's Forest department has sought compensatory land equivalent to twice the area, or 8.92 hectares. The Chengalpattu district administration has identified alternative land at Veda Narayanapuram near Chengalpattu, but the forest-land clearance process has remained unresolved for nearly two years.

The issue had earlier caused confusion at the Central Forest department because proposals for the Perungalathur ROB road connection and the Tambaram Eastern Bypass involved forest land in the same area. The Highways department subsequently clarified that the two were separate projects.

Residents are now questioning why the opening of a completed ROB arm should depend on the progress of the bypass project. Mahendra Boopathy, president, Perungalathur-Peerkankaranai Residents Welfare Association, said the two projects should be delinked.

"The Perungalathur ROB and the Tambaram Eastern Bypass are two separate projects. The ROB arm is almost complete. The only issue is the narrow stretch where it descends and joins Nedunkundram Road. That portion can be widened and the ROB can immediately be opened for public use," he said.

He added that the waiting for the entire bypass project could delay the opening of the ROB arm by another one or two years. "The narrow portion should be rectified and the ROB should be opened immediately. At present, the eastern arm towards Nedunkundram remains closed, making the massive ROB effectively stand on three legs instead of four," he said.

For residents, the irony is stark: an infrastructure project first proposed 26 years ago has finally reached the stage where one of its arms is fully constructed, but motorists are still being denied access because a separate road-widening project is waiting for forest-land clearance.