High-speed railway catenaries are vital components in railway traction power supply systems. To ensure stable contact between the pantograph and the catenary. droppers are positioned between the messenger wire and contact line. The failure of one or more droppers will affect the power supply of the catenary and the operation of the railway. https://www.roneverhart.com/PG201004AV-Air-Compressor-Tank-Bushing-2-X-1-4-Campbell-Hausfeld/