COST-BENEFIT ANALYSIS OF SLEEPER REPLACEMENT STRATEGIES: SIMULATION MODEL

A simulation model predicts the condition of a section of timber-sleepered railway track, including the clustering patterns of the defective sleepers and the cost of replacement under a given strategy. These results are used to perform a cost-benefit analysis of the different possible strategies for the replacement. For the simulation model, it is assumed that the life of a timber sleeper is represented by the Weibull distribution. User-controlled inputs include the length of track and the number of years to be simulated. Results generated from the model include the percentage of defective sleepers, the average life remaining, the number of clusters of various sizes, the number of sleepers replaced, and the total cost of the strategy. Investigation was conducted into the length of track that should be simulated. The length depends on the required reliability of the model. The simulated replacement strategies are compared on the basis of cost and resulting track condition