ACTT™ Automated Railroad Concrete Cross Tie Testing

Regular testing of concrete railroad cross ties is critical to the safe operation of high-speed rail systems. Current inspection and monitoring of the condition of railroad cross ties is limited to visual inspection of the exposed top surface – most of the tie, and any defects, are hidden from view.

NDT’s Automated Concrete Tie Testing — ACTT™ — is a mobile, non-destructive testing system for condition assessment of concrete rail ties. ACTT uses sonic/ultrasonic techniques for reliable scientific testing of the structural performance of railroad cross ties.

ACTT provides:

  • Quantitative Measurements
  • 3 MPH Non-Stop Data Acquisition
  • Auto-Assessment of Data
  • Immediate Marking of Bad Ties
  • Automated Data Storage & Analysis

ACTT determines the integrity and condition of each tie by measuring and recording the velocity of acoustic waves propagated through prestressed concrete railroad cross ties.

ACTT propagates an energy wave and uses the concrete tie as wave guide, measuring the travel time of the wave across the railroad tie as ACTT moves down the rails at three miles per hour. The measurements detect and quantify internal flaws that visual inspection misses because of the limited exposed railroad tie surface. ACTT processes the data and marks damaged ties in real time, with results available as printouts and data files.

Capabilities Used


  • R&D Project
    Federal Railroad Administration

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