Increased Axle Loading and Speeds on the Sishen-Saldanha Iron Ore Export Line in South Africa

摘要

Eighteen months after increasing the axle loadings from 26t to 30t on the 863 km iron export line (1067 mm gauge) rapid track degradation was reported. Slacks and crushed ballast resulted from dipped butt welds. Track Technology carried out extensive strain measurements to determine the maximum dips permitted. Tests were done at different speeds and with resilient rail pads. A dip trolley measurement car was developed and measurements taken before every grinding cycle. A mechanical semafir was modified to replace measurements of dips by straight edge and feeler gauges. Results were used to determine dip growth. Top of rail profile was determined with geometry measurement car. Increased speeds are now evaluated and expected increased maintenance cost.