FUZZY MULTI-ATTRIBUTE DECISION MAKING FOR THE SELECTION OF A SUITABLE RAILWAY TRACK MAINTENANCE PLAN: A CASE STUDY IN THAILAND

Degradation of infrastructure has affected service quality; in other words, the rail freight transportation rate has been considerably low at only 2%. As a result, for the purposes of safety and highreliability levels in infrastructure, several organizations have conducted serious research on the interesting topic of railway track degradation. As the focus of the present study was degradation factors, the Fuzzy MultiAttribute Decision Making Method (FMADM) was used to analyze railway track defects and degradation and to select a maintenance plan schedule. Related research and literature were reviewed, and a questionnaire was designed to collect opinions from experts working for the State Railway of Thailand (SRT). The experts prioritized risk levels likely to result in the worst breaks or damage, using UIC defect codes. These consisted of transverse break defects without apparent origin (code 200) with the highest level of impact and relative weight of 0.396, followed by star-cracking of fish bolt holes (code 135) with a relative weight of 0.276 and transverse cracking of profile thermite welding (code 421) with a weight of 0.187. The least severe impact was said to come from horizontal cracking at web-head (code 1321) with a relative weight of 0.142. Analysis results based on FMADM indicated that the railway track structure replacement plan, as considered by the experts, was better than the railway track rehabilitation plan, as shown by their importance weights of 0.575 and 0.425, respectively.