The paper deals with functional and safety analysis of transmission in railway control systems, especially fail-safe applications (Line Block System, Dispatcher/Interlocking, Cross Level Protection and monitoring remote control). An analysis of the data structure is presented with recommended protection mechanisms to determine the indexes of time used for safety proof. The typical standards used in safety transmission systems are A0-A1 (with additional data - e.g. time stamps and safety code- -CRC), B0 (enciphered message containing user data, non-cryptographic safety code and additional data) and B1 (with additional data, non-cryptographic safety code, and cryptographic code). These methods correspond to the existing standards (EN-PN 50159-2, EN PN 50 129, EN PN 50126) and are recommended for safety transmission analysis in new railway control systems with public wireless transmission.