NFR deploys underwater robots to inspect Saraighat Bridge over Brahmaputra

The Northeast Frontier Railway (NFR) has undertaken a major technological upgrade in bridge safety by deploying advanced Remotely Operated Robotic Vehicles (RORVs) for underwater inspections of key railway bridges across the region. 

The initiative has enabled detailed structural assessments of vital bridges whose foundations remain submerged throughout the year.

One of the major structures inspected is the historic 1.45-km Saraighat Bridge over the Brahmaputra, India’s first rail-cum-road bridge and a critical link between Pandu and Amingaon. 

NFR used a combination of RORV surveys, LiDAR, thermal imaging, Ground Penetrating Radar (GPR) and Ultrasonic Pulse Velocity (UPV) tests to examine underwater scour zones, well foundations, pier caps, deck components and superstructure stress points.

In the Alipurduar (APDJ) Division, 18 important bridges were also scanned using RORVs, which captured high-resolution visuals of submerged piers, riverbeds and hidden structural defects. Officials confirmed that no major underwater defects were detected in any of the inspected structures.

During 2024–25, NFR conducted underwater inspections of 13 bridges, while 34 more have already been covered in 2025–26. The data gathered is helping improve the accuracy of structural health monitoring, enabling timely preventive maintenance.

NFR said the adoption of RORV technology, paired with modern digital assessment tools, marks a significant advancement in scientific bridge inspection methods. 

It reaffirmed its commitment to enhancing the safety and longevity of major bridges—particularly key assets like the Saraighat Bridge and other vital structures that ensure uninterrupted rail connectivity across the Northeast.