The article analyzed the system of "manual" analysis of the rail NDT results operating on the network of JSC "Russian Railways." The most of decrypter’s work time is spent on routine work not related to search for signals from defects. Difficulties were noted in creating programs for automatic decryption of defectograms. Invention proposes solutions to increase efficiency and reliability of defectogram decoding. Keywords: rails, defects, generalizing parameter, defect development, automatic decoding.