Complex system of rails diagnostic has been implemented in Russia to provide railway traffic safety. The system is based on three groups of NDT means: one of which is NDT means for rail inspection. It includes: portative ultrasonic flaw detectors which register all the results in mode B-scan, combined flaw detectors, based on ultrasonic and magnetic methods, inspection motorailers and railcars, portative programmed ultrasonic flaw detectors with independent power supply. Statistics on amount and results of rail and weld inspection both at the railways and at rail welding plants is given. Probability of defects detection is 0,992 – 0,999.