Degradation Processes of Railway Switches: to Improve Maintenance

Approximately 25 percent of the budget for the maintenance and renewal of railway tracks ?in Switzerland more than a billion Swiss Franks? is used for the switches (a.k.a. points or turnouts) and crossings (S&C). While in the mean time the budget expenditure for the maintenance and renewal of plain track is optimized with e.g. the help of decision support systems, for S&C this optimisation stays rather rudimentary. One of the identified causes thereof is the lack of insight in the degradation and deterioration process of S&C. This study therefore combined several databases of the Swiss Federal Railways (SBB CFF FFS). Statistical analyses are carried out on them to retrieve the lifetime of expectancy of complete railway S&C and their respective components, e.g. point rails, stock rails, frog. The expected lifetimes are attributed to different parameters which influence the speed of geometrical degradation or wear of the material, e.g. total train loads (expressed in cumulative tonnages), axle loads, the main direction of the trains, the speed and the quality of the foundation.