Rail infrastructure is used to examine the relationship between corrective and preventive maintenance. 70–90% of costs are tied to corrective maintenance.
To show the relationship between preventive maintenance costs and corrective maintenance costs, a study was run examining railway infrastructure maintenance in the US. In the case study, the 10 most expensive railway sections were found to have four times higher maintenance cost than the 10 least expensive railway sections. This is attributed to the fact that the costliest sections transported three times the tonnage compared to the sections with the lowest costs. For this reason, the costliest sections also experienced 4.5 times more track failures.
Corrective Maintenance Savings
Delving deeper into the maintenance costs reported, it was determined 70– 90% of the maintenance cost comes from corrective maintenance, which constitutes 61% of downtime (DT) and delay costs (see more on the 6:1 Golden Rule of Preventive Maintenance). Consequently, the results depend on the cost of DT. However, if the DT cost is disregarded in the case study, corrective maintenance still stands for 50 –70% of the maintenance cost of the railways. Corrective maintenance will always be necessary in an industry like railroads, where some variables are unpredictable, such as weather patterns that could rust railroad tracks or send trees falling. However, preventive maintenance can help ease the burden in cases where variables can be controlled.
Preventive Maintenance Savings
While the costliest sections have the highest share of corrective maintenance, it was also found that the railway sections with the lowest total maintenance cost have the largest share of preventive maintenance: 30% preventive maintenance costs in the least costly sections – compared to 10% preventive maintenance costs for the costliest sections. This could be related to the difference in extent of the inspection frequency and quality. However, it was also found the railway sections with the lowest cost have lower preventive and corrective maintenance costs, which would be due to the fact that the highest cost sections were transporting three times more tonnage. This is an example of why insiders must run effective cost-benefit analyses to decide which is best for their company regarding their industry and variables.
Preventive maintenance and corrective maintenance are both necessary for railway infrastructure to run successfully, however the costliest and least costly sections should be analysed differently due to the fact they transport extremely different amounts of tonnage. This fact holds true in any industry where operations might differ from each other. An effective cost-benefit analysis can help companies decide which maintenance system might be most efficient for them, when applying the tips and rules mentioned in our summar of the cost benefit analysis of preventive maintenance.
References: Christer Stenström, Per Norrbin, Aditya Parida & Uday Kumar (2016) Preventive and corrective maintenance – cost comparison and cost–benefit analysis, Structure and Infrastructure Engineering, 12:5, 603-617, DOI: 10.1080/15732479.2015.1032983