Breakage of a front rod by environmental conditions of turnout and switch devices have been one of the issues of maintenance of signalling devices. In this paper, we investigated the relationship between environmental conditions and front rod strain by the failure history of railway operators, on-site survey, and measurement tests at switches when a train passes through. As a result, we confirmed that the impact, when the wheel passes over the joint with difference of elevation at the end of the tongue rail, affects the strain and stress fluctuations on the front rod. Based on these results, we also proposed inspection methods of front rods.
