AUTOMATED ULTRASONIC INSPECTION OF RAILS

The company STARMANS electronics, s.r.o., in co-operation with Brazilian company NDT do Brasil, has developed and realized 24-channel automated system for operational ultrasonic rail inspection.
Fig.1: Testing equipment hanged on the modified truck.

Automated system for operational rail inspection comprises of the following parts:

  • Controlling PC, which serves for setting of testing parameters (all parameters are adjustable independently for each channel), saving and loading setting configurations, data acquisition, processing and archiving.
  • 24 ultrasonic channel unit modules.
  • Equipment for data transfer and synchronization from the channel units.
  • Software for data displaying and processing.
  • Mechanical and hydraulic equipment for wheel probes hanging and guiding on the rails.
The system is equipped with 4 wheel probes (see Fig. 2 and 3), each contains 6 transducers: one 0 deg. transducer for vertical part of the rail and, at the same time, for acoustic coupling monitoring; one 45 deg. transducer along the rail axis for detection of cracks from bolt holes; one 45 deg. transducer perpendicular to the rail axis (side-looker) for detection of longitudinal defects in the head area; three 70 deg. transducers along the rail axis for detection of transverse cracks in the head area.




Fig.2: Wheel probe with several transducers for inspection of rails.
Fig.3: Wheel probe for rail inspection.

Testing sensitivity is adjusted on the artificial reflectors - side drilled holes 2, 3 or 5 mm diameter drilled in the head area, vertical section and, if required, in the foot area. Achievable testing speed is up to 50 km/h, depending on specific requirements. During inspection of both rails simultaneously, two wheel probes are used for each rail in such a manner, that transducers cover both directions along the rail axis. Each transducer in 4 wheel probes is connected to separate DIO-2000 channel unit. During inspection, each channel executes digital data processing including evaluation by amplitude and location of indications. Data outputs from ultrasonic channels are connected to controlling PC, which further processes, evaluates and displays data on the LCD monitor and archives database in files by sections of inspected rails. DIO-2000 software uses modified B-scan for presentation of test results, where displaying of indications is synchronized regardless on actual transducers arrangement in all wheel probes - see Fig. 4. Indications from individual channels are separated by colour.


Fig.4: Graphic presentation of inspection record.

Software DIO-2000 enables monitoring of individual indications development during inspection, acoustic coupling monitoring, actual testing speed and the length of inspected section. Data about detected indications (registered indications, their number, relative position in the track etc.) are recorded in database. Software enables to record courses of A-scans, which may be played later like "videorecording" and re-evaluated after testing and data acquiring process had been finished.

More details about testing of rails can be downloaded in PDF file.