Summary. In this article, for the first time, research of the defective frog wing of the 1/11 mark on the Latvian Railway has been carried out. In the process of which was collected, processed and the analysis of points defects on the Latvian Railway was carried out for eight compartments of the track distance during 2014, 2015 and 2016 (Developed a chief of defectoscopy shop V. Glotov, approved CD the chief of the distance V. Makedon). The frog wing of the 1/11 mark (the 60 E1 DO 04 07 frog type) was considered according to the basic classification of the defects, and an analysis and research of the cause of its fracture were carried out.