A new technique of the "first and second limits" for wagon maintenance in railway tracks consisting of sharp curves based on the empirical study of wheel wear

Wheel wear is one of the maJor costs in railway tracks consisting of sharp curves. In this paper, wear behavior of S1002 profiles of wheels in the "Southern Line" of Iranʹs railway, which consists of a large number of distinct and/or consecutive sharp curves, is studied using the field data measuring technique. Based on wear behavior analysis of all wheels, an optimal wagon maintenance technique called the "first and second limits" is suggested to minimize the wagonʹs cost per traveled distance. The results show that: 1) A severe wheel flange wear occurs for all wheels in comparison to the wheel tread wear in normal tracks; 2) A wagonʹs detachment for repair of critical wheels on its four axles occurs at the traveled distances of 40,000 km, 54000 km, 71000 km, and 75000 km, respectively (much less than the normal traveled distance of 500,000 km); 3) A fifth order polynomial function can be appropriated to represent the wear behavior of the wheels; 4) By implementing the suggested technique, the cost per traveled distance decreases by 38.64%, and the travelled distance increases by 45%.