UDS2-73 Purpose

The flaw detector is intended for defects detection in both rails along the running surface and rail cross-section, except for the rail base blades using flaw detection trolley during complete testing, and for the confirmatory testing of separate rail cross-sections and welded joints by means of manual probes.

Flaw detector advantages

  • Rail complete ensounding (except for the base blades), due to the flaw detector multi-channeling;
  • built-in standard setups for channels operation;
  • defining the traveled distance and motion speed during the complete testing;
  • real-time testing results display in B-scan mode (by 4 channels);
  • ensounding and saving the information in every millimeter of traveled distance via all channels is provided in the flaw detector;
  • testing results record at different sensitivity levels;
  • registration of all testing results and advanced capabilities of data analysis;
  • the flaw detector with the base sounding scheme application allows to detect all types of fatal defects, appearing while rail track operation.

Flaw detector distinctive features

  • Large color high-contrast TFT display;
  • synchronization by encoder;
  • information display forms: А-scan, B-scan;
  • number of channels for complete testing: 26;
  • number of channels for manual testing: 2;
  • techniques and areas of rail head testing:
    • echo technique by angle-beam probe for the testing of field and gage side of railhead along and against the movement;
    • echo technique by angle-beam probe for the testing of central part of railhead along and against the movement;
    • echo-mirror technique by angle-beam probe for the testing of central part of railhead along and against the movement;
    • echo-mirror technique by angle-beam probe for the testing of field and gage side along and against the movement;

Fig. Echo techniques for railhead testing

Fig. echo-mirror techniques for railhead testing

  • Techniques and areas of a web testing and its projection in the base:
    • echo and echo-images techniques by straight-beam single-crystal probe for detection of longitudinal horizontal cracks;
    • echo techniques by angle-beam probe along and against the movement for detection of transverse cracks and testing of bolt holes;

Fig. Echo techniques for the web and base testing

Flaw detector using the base sounding scheme enables to detect all types of fatal defects with the following features:

Fig. - Types of sharp-defective rails

  • transverse cracks in the 2nd-category railhead, including well-developed transverse cracks with reflecting surface and also the ones developing under horizontal roll surface separations which are not detected by standard echo technique;
  • longitudinal horizontal cracks in the web, even if they did not reach the rail axis in their development, and also in the head, including the ones that do not go beyond the web projection;
  • longitudinal horizontal cracks located in the middle of the rail height;
  • cracks from bolt holes, including the ones in early stage of their development when they do not go beyond the bolt hole projection to the roll surface;
  • vertical cracks in the base and web located mainly along the rail axis;
  • transverse corrosion cracks in the base located in the web projection area.

Instrument service functions

  • Sound and visual alarm, modes switching with the help of "hot buttons";
  • possibility of electronic registration of testing results by all channels allow to perform their reinterpretation and make complete reports;
  • mode of defyning the rail type and automatic correction of setups;
  • mode of bolt holes testing by special setups;
  • for in-depth analysis of detected signals, except for the usual information display in the form of А-scan, the B-type sweep is used in real time by one, two, four channels (left and right rail of driving into and driving out channels) is applied;
  • possibility of TCG curve (of any shape) plotting.

Fig. Modes of testing results display in A-scan and B-scan on the flaw detector screen

Additional software

"LuCH-Controller 1.6" is intended for viewing and analysis of testing results of UDS2-73 ultrasonic rail flaw detector and serves for interpretation carrying out and display of information on suspicious rail sections. The present program provides operation with the data stored on a personal computer.

Main advantages of program application are:


  • Convenient operation with the tested sections (spans) database;
  • possibility of selection of various grouping of testing channels, testing rail, rail testing area, testing technique;
  • possibility of conditional dimensions measurement in B-scan mode;
  • possibility of А-scan viewing by the stored data in B-scan mode;
  • possibility of movement throughout the defectogram (B-scan) by means of scrolling mode or mode of fast shift to the set coordinate;
  • "Position marks" mode for suspicious rail sections marking during testing results viewing;
  • mode of testing results filtering by the sensitivity level from minus 6 to plus 6 dB relative to ALARM level;
  • mode of viewing and generation of reports on the selected testing section.

Main specifications:

Overall dimensions of flaw detector without a handle and with one ultrasonic unit and power unit no more than (1040×1640×1130) mm;
in transport position – no more than (900×2060×600) mm.
Equipped flaw detector weight no more than 75 kg.
Keypad English, Russian.
Languages English, Russian.
Number of ultrasonic units 4
Number of ultrasonic channels 28 channels.
Connector types BNC, RS-19.
Data storage Flash card.
Independent power source
NiMH storage battery of rated voltage 12 V and rated capacity 17 А∙h.
Operation time 8 hours.
Flaw detector consumed electric power no more than 30 V•А.
Time of flaw detector operation mode setup no more than 15 sec.
Display resolution 800×480 pixels.
Screen dimensions (width, height, diagonal) 155 mm, 95 mm, 180 mm (7.5 inches).
Warranty 1 year.
USB USB-A (host), USB-B (slave).
Trigger O available.
Headphones available.
Encoder output Single-coordinate encoder.
Main metrological performances
The limits of admissible main absolute error of flaw detector during the measurement of depth and coordinates, of defects depth
  • = ±(0.5+0.02НY) mm;
  • = ±(0.5+0.02Х) mm;
  • = ±(0.5+0.02Y) mm.
The limits of admissible main absolute error during the measurement of signals amplitudes ratio ∆N at the reception path input in the gain range from 20 dB to 80 dB

∆N = ±(0.2+0.03N);

∆N ─ main absolute error during signals amplitudes ratio measurement, dB;
N ─ numeric value of signals amplitude ratio, dB.

Time instability of flaw detector reception path sensitivity ± 0.5 dB for 8 hours of continuous operation.
Protection level in operation IP 64
Ambient temperature from minus 400 to plus 500С.
Atmospheric pressure from 84 to 106,7 kPa.

Relative humidity
(93 ± 3) at a temperature 25 ºС.
Flaw detector in shipping package is resistant to the influence of
  • vibrations;
  • strokes with the peak shock acceleration value 98 m/s2, impulse duration 16 ms, number of strokes 1 000±10 for each direction.
Flaw detector retains its parameters when it is influenced by electromagnetic interferences which do not exceed the following norms
  • harmonic interferences of magnetic field in the frequency band from 30 Hz to 50 kHz with the effective value of field intensity from 130 to 70 dB;
  • harmonic interferences of electric field in the frequency band from 10 kHz to 30 МHz with the effective value of field intensity 120 dB.
Full average flaw detector lifetime no less than 10 years.
Probability of no-failure operation no less than 0.9 for 2 000 h.
Initial pulse type Short pulse of negative polarity.
Initial pulse frequency One-channel mode – 250 Hz; complete mode – no more than 1000 Hz.
Amplitude 180 V
Duration 60±10 ns
Rising edge duration no more than 20 ns.
Synchronization type from an initial pulse, from an encoder.
Gain from 0 to 100 dB with a step of 0.1, 1, 10 dB.
Input signal no more than 2 V from a peak to a peak.
Input reception path resistance no more than 300 Ω.
Digital filter 1 standard digital filter with central frequency 2.5 MHz.
Rectifier envelope.
Setups mode
Measurements mm
Testing range from 0 to 1000 mm, with a step 1, 10, 100 mm.
Velocity from 2000 m/s to 8000 m/s, with a step 1, 10, 100, 1000 m/s.
Probe zero from 0 to 60 µs, with a step 0.1, 1 µs.
Range delay from 0 to 1000 µs, with a step 1, 10, 100 µs.
Probe angle from 0 to 900, with a step 10, 100
Number of cycles max. number of cycles 16.
Cycle duration 0.01 - 0.4 ms.
Number of gates in a cycle max. number of gates 2 for each channel.
Gate fixation level from 0 % to 100 % of vertical screen scale.
ALARM When the signal goes beyond the ALARM level, when the signal stays within the ALARM level.
ALARM system
Sound ALARM system sound – separate for each rail and combined (for a group of channels);

range of pulse frequency setup of alarm system sound indicator is from 0.5 to 5 kHz, with a step 100 Hz.
Light ALARM light – separate for each rail and combined (via all ensounding channels);
visual by the screen – separate for each rail and each channel.
Measurements in A-scan mode
Displayed parameters 4 measuring parameters are displayed in a status bar.
  • А – amplitude of an echo-signal from a defect in relation to ALARM level, dB;
  • S – distance "by the beam" to a defect;
  • X – defect depth coordinate, mm;
  • Y – defect depth coordinate, mm.

TCG curve

max. number of points is 14 per cycle, dynamic range 100 dB, vertical setup step 1 dB, horizontal – 2 mm.
Measurements in B-scan mode
"Raw" B-scan
  • А – max. amplitude of the echo-signal from the defect relative to the screen center, dB;
  • H – distance "by the beam" to the defect an echo-signal from which has max. amplitude, mm;
  • dH – conditional length "by the beam", mm;
  • L – coordinate along the scanning path to a defect an echo-signal from which has max. amplitude, mm;
  • dL – conditional defect length, mm.

Delivery set of ultrasonic rail flaw detector UDS2-73 (v.3.0)

  • View Far-abroad countries
  • View Appendix B.List of spare parts (Far-abroad countries)

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