The article analyses the problem of synthesis of the systems of safe control of critical technological processes on the example of railway automation and remote control systems.It is shown that modern control systems for complex distributed systems, such as a railway transport system, are not implemented with absolute safety. The safety of such systems is limited by considering only their own failures, external failures of control systems and their components, as well as failures of infrastructure objects that directly interact with control devices. Other infrastructure facilities are not considered in any way during automatic control and data transfer to on-board automation.The objective of the article is to present theoretical concept of the synthesis of safe train traffic control systems, considering the capacity of equipping infrastructure facilities with highly reliable and safe means of technical diagnostics and monitoring.A shown simplified structure of the central train traffic control centre considers the results of diagnosing and monitoring all the components of the transportation process.The conditions for the synthesis of completely safe train traffic control systems are formulated along with the accompanying tasks. A comprehensive accounting of the parameters of railway infrastructure facilities and rolling stock will allow reaching a qualitatively higher level of train traffic safety.