The ТОМОGRAPHIC UD4-TM (2.69) is a single-line ultrasonic flaw detector designed to search, record and interpret signals from flaws in the rail base. Testing is carried out from the rolling surface of the rail, tested zones are web-base transition and base flange. The movement speed of the scanner is 5-7 km/h. TOMOGRAFIK UD4-TM (2.69) is an effective remedy of control of rails on the railway crossings which are most subject to corrosion.