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In the present study, weight functions (WFs) of a subsurface crack were derived by proposing a new general form for approximate one‐dimensional WF. The WFs coefficients were considered as a function of crack length to depth ratio and were obtained using reference stress intensity factors (SIFs) of 16 cracks under uniform, linear, and parabolic normal and shearing loadings. The verification was performed by comparison of the straight and coupled SIFs calculated by WF and finite element modelling under some complicated loadings. In conclusion, the WFs can be simply and effectively employed for evaluating the cracks under any complex stress distributions.

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After the application of the newly purchased passenger coaches by the Iranian railway transportation system, numerous reports showing passengers’ dissatisfaction with the frequent vibrations of these coaches were prepared by the technical agents. To review the reasons of these vibrations and efforts to remove them, bogies, wheelsets, and suspension systems of the coaches were first evaluated. Preliminary studies suggested that wheel hollowing can be the most probable reason of these vibrations. Thus, for a more detailed study of this hypothesis, a field study was prepared. To do so, the wheel profiles of 100 coaches were measured in a controlled manner in a period of 6 months. The results out of these measurements indicate that the criterion and workshop equipment applied for the measurement of wheel hollowing in Iranian railway systems is not able to show the hollowing of these wheels properly and coaches operation with such wheels causes severe vibrations in these types of coaches. To avoid this problem, two solutions were proposed.