Determining residual stresses in operating railroad tracks

The residual stresses occur in the material structure of unloaded solid bodies, reflecting their technological path, together with the history of mechanical and thermal loads incurred during their operation. It is important to underline that the residual stresses in a solid body have always the effect of a balanced system of forces. When they overlap with the stresses involved by the loads for which the body is intended, it is sometime possible for that body to be taken out of operation. Experimental tests covered by this work aimed to highlight some possible degradation occurring during the operation for the railroad tracks called '85 and '86, in order to establish to what extent they may still be used for another time interval. In this context, the size of residual stresses was experimentally determined, in some samples taken from the studied railroad tracks, and also from a piece of unused railroad track, in order to compare the results. Moreover, an analysis was made, using the specifications of the standard SR EN 13674-1:2011, on the variation of stresses that occur in the material during the rails cutting.