Assessing the Performance of a Heavy Haul Railway Viaduct Through Monitoring Traffic Loads and Dynamic Effects

South Africa is one of the leading countries in heavy haul railway freight transport. At present, it operates the longest freight train in the world, 4.1 km long and consisting of 342 wagons, to export iron ore. Moving loads induced by trains on bridges are repetitive in nature thus leading to possible excitation of the deck, and a very long sequence of wagons with identical wheelset distance may magnify this effect. The paper presents an ongoing monitoring program of the Olifants River Viaduct, a large-scale multi-span bridge crossed by the long freight train. Focus is given to both monitoring of traffic loads and dynamic effects.