Northeast Frontier Railway underwater inspections

Northeast Frontier Railway underwater inspections now sit at the heart of how the zone evaluates the condition of its major bridges.

This is reported by the railway transport news portal Railway Supply.

The work is carried out with advanced Remotely Operated Robotic Vehicle (RORV) systems, as reported by ET Infra. These surveys cover critical structures across the network, from the landmark Saraighat Bridge over the Brahmaputra to several important bridges in the Alipurduar (APDJ) Division.

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Northeast Frontier Railway underwater inspections at key bridges

According to Kapinjal Kishore Sharma, Chief Public Relations Officer (CPRO) of NFR, many of these bridges have substructures that stay under water throughout the year. Because of that, underwater bridge inspection and scour assessment are essential to understand the state of foundations, wells and piers and to keep overall bridge safety in Northeast India’s rail network under control.

The historic Saraighat Bridge — India’s first rail-cum-road bridge across the Brahmaputra River, stretching 1.45 km between Pandu and Amingaon — has become a central focus of these structural health monitoring activities. Its latest Saraighat Bridge RORV inspection brought together several advanced techniques: RORV-based underwater surveys, LiDAR scanning, thermal imaging, Ground Penetrating Radar (GPR) and Ultrasonic Pulse Velocity (UPV) testing, as also highlighted in ANI-based coverage on LatestLY.

Using this combined digital toolkit, NFR engineers examined pier caps, well foundations, underwater scour zones, critical stress points in the superstructure and key deck components.

RORV technology in the Alipurduar Division

In the Alipurduar Division, 18 significant railway bridges have gone through similar in-depth checks. Here, the Remotely Operated Robotic Vehicle supplies high-resolution visuals of submerged piers, the riverbed and potential defect zones that are difficult or impossible to reach with traditional methods.

Across all bridges inspected so far under this programme, no major underwater defects have been detected, which confirms the current condition of key structures while still supporting timely preventive maintenance.

During 2024–25, NFR completed underwater inspection of 13 bridges using RORV technology. In 2025–26, up to December 2025, structural inspections of a further 34 bridges have already been carried out. Taken together, these figures show how systematically NFR is applying underwater robotic vehicles for bridge safety across its network, especially on vital connectivity routes.

Structural health monitoring and preventive maintenance

By feeding precise underwater and structural data from RORV surveys, LiDAR, thermal imaging, GPR and UPV into its monitoring processes, Northeast Frontier Railway strengthens the accuracy of structural health monitoring and can schedule preventive maintenance before issues escalate.

This scientific bridge assessment approach is particularly important for major crossings such as the Saraighat Bridge and for other bridges that support rail connectivity for Northeast India.

NFR indicates that it will continue to use modern technologies and digital inspection tools to safeguard and extend the life of its major bridges. The ongoing programme of underwater inspections with RORV and related scanning methods marks a steady step forward in how the railway manages bridge safety in the region.

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