Guwahati: The Northeast Frontier Railway (NFR) has successfully conducted extensive underwater and structural inspections of major railway bridges using advanced Remotely Operated Robotic Vehicle (RORV) technology, officials said on Sunday.  

This RORV technology includes critical bridges such as the iconic Saraighat Bridge over the Brahmaputra and several important bridges under the Alipurduar (APDJ) Division in North Bengal.

NFR’s Chief Public Relations Officer (CPRO) Kapinjal Kishore Sharma said that the major railway bridges have substructures that remain submerged year-round, making underwater inspection essential for assessing the condition of foundations, wells and piers.

The historic Saraighat Bridge in Assam, India’s first rail-cum-road bridge over the Brahmaputra River, spans 1.45 km and connects Pandu and Amingaon. As one of the most vital rail–road lifelines of Northeast India, it was inspected using a combination of RORV surveys, LiDAR, thermal imaging, Ground Penetrating Radar (GPR) and Ultrasonic Pulse Velocity (UPV) tests.

The assessments covered pier caps, well foundations, underwater scour zones, superstructure stress points, and deck components.

In the APDJ Division, 18 important bridges were inspected thoroughly, with RORV capturing high-resolution visuals of submerged piers, riverbeds and potential defects, the CPRO said.

According to Sharma, across all these structures, no major underwater defects were detected. During 2024-25, NFR completed underwater inspection of 13 bridges using RORV, and during 2025-26, 34 additional bridges have already been inspected, he stated.

These insights enhance the accuracy of NFR’s structural health monitoring and support the timely planning of preventive maintenance.

The official said that the NFR remains committed to utilising modern inspection technologies to ensure the continued safety and longevity of major bridges across the region. The application of RORV, coupled with advanced digital tools, marks a significant step forward in scientific bridge assessment.

NFR will continue strengthening its inspection framework to safeguard critical connectivity routes, especially structures like the Saraighat Bridge and key bridges under NFR, which are central to rail operations across the Northeast region.

The Northeast Frontier Railway (NFR) operates in the Northeastern states and in seven districts of West Bengal and five districts of northern Bihar.