In this paper, mechanical stresses on railway traction line insulators are analyzed by structural analysis. In application of railway traction lines, insulators are not only used to insulate but also subjected to adverse environmental conditions and mechanical vibrations. Two kinds of test to verify the robustness of insulators are performed in this study. Cantilever load test and tensile force test are carried out to ensure the reliability and stability of railway traction line insulators. Structural analysis that focuses on cantilever load test and tensile force test is carried out by using COMSOL Multiphysics. Finally, safety factors of each railway insulator are presented as results.