Railway Overhead Wiring Structures in Australia: Review and Structural Assessment

Overhead wiring structures (OWS) provide physical support to overhead electrical wires that power trains. They are typically spaced at 50 to 70 m. In a rail network, tens of thousands of these structures are required. Although they are simple structures, due to their numbers; design, construction and maintenance often involve large capital investments. Their reliability is also crucial to a safe operating rail network. This paper presents a review of OWS in Australia. Electrification of train services began in the 1910s, making some of the OWS over 100 years old. Descriptions in this article include their structural forms, design, construction, assessment and maintenance. It follows with a structural assessment carried out on a century-old riveted OWS built in the 1910s. This OWS was decommissioned in a recent railway renewal project which allowed the assessments to carry out. The assessment provides insights into hundreds of similar aged OWS still being used today. Assessments carried out consisted of tensile tests, corrosion depth measurements, radiographic imaging, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). Crevice corrosion is common in locations where moisture accumulated. Material properties were similar to modern-day Grade 250 steel with satisfactory ductility. Corrosion depths were less than those predicted. Samples of riveted connection showed no sign of deterioration within connected plates. This study may provide insights into structural design, construction and maintenance of similar structures in Australia and abroad.