Stray current monitoring and control on Singapore MRT system

Stray current corrosion on railway infrastructure and nearby utilities by direct current railway track return system has been an issue for many years. Control and mitigation of stray current has been an important aspect of direct current railway track return system. This paper briefly discusses various design parameters and installation practices of stray current corrosion control and monitoring system applied in Singapore MRT tunnels, viaducts, depot and at grade sections. This paper also covers some basic concepts of stray current corrosion in direct current railway track return system. It also outlines some adopted testing and commissioning methods for both prerevenue service and post revenue service periods. Evaluation and assessment of test/measurement results as well as regular inspections and tests for preventive maintenance of stray current corrosion and mitigation are also discussed.