The ACFM Walking Stick instrument provides a thorough NDT analysis of surface breaking rail-head defects.

Defect pocket-depth analysis is automated and can discriminate between gauge corner cracking and other defect types.

The system utilises advanced windows software, developed by TSC, which automatically analyses the data on-site and can produce yard-by-yard inspection summary reports.


Following rigorous site trials by an independent UK rail technology company, the system has been found reliable and capable for identifying and classifying small and large Rolling Contact Fatigue (RCF) cracks. This efficiently allows:

  •  Maintenance strategy planning based on rail categorisation
  •  Defect monitoring following maintenance/grinding



Walking Stick offers the following

  • Inspects the whole rail head surface in one pass .
  • Audible warning of defects.
  • Deepest defect per yard automatically reported and sized .
  • Longitudinal position in miles and yards on rail recorded.
  • Battery life in excess of 5 hours continuous use (easy swap).
  • Automated export of inspection summary in Microsoft® Excel format.
  • Import and archive of all inspection data on an office based system.


The ACFM Walking Stick does not suffer from some of the problems of conventional ultrasonic inspection techniques where large numbers of defects can render a rail un-testable. With ACFM, the deeper the crack, the larger the response.

Use of the Walking Stick has many advantages, including:

  • Use as a primary inspection tool on plain line inspection to determine the presence of surface breaking rail head defects.
  • Categorising rail for assessing the maintenance strategy.
  • Inspection before grinding to assess the amount of material removal.
  • Post grinding inspection to confirm the removal of defects.
  • Monitoring crack growth/re-growth to assess the effectiveness of maintenance strategies and machine grinding frequencies.


Unit Weight 21kg
Unit Size 700mm x 300mm x 1000mm
Scan Rate 15 m/min
Typical Operating Speed 1.5 – 2 mph (2 – 3 km/h)
Probe Support 16 channels plus position encoder
Power Requirements Integral 12V battery supply, recharged by domestic 110V or 240V AC 40 / 50 Hz supply.
Operating Temperature -20º to +40ºC
Environment Protection IP54 rated
Minimum PC Requirements Processor 500MHz, 128Mb RAM, 40Mb hard drive, serial port or one free USB port
PC OS Requirements Microsoft Windows NT/2000/XP


The size, weight and long battery life of the Walking Stick makes the instrument ideal for use on rail.

Together with a rugged notebook PC, inspection can be carried out in almost any location and in adverse weather conditions.

The system is designed to be easily placed on the rail and collect data quickly. Removal from rail in the event of traffic is fast and all data collected, however small is automatically saved, together with a yardage position.

The ACFM Walking Stick does not suffer from some of the problems of conventional ultrasonic inspection techniques where large numbers of defects can render a rail un-testable. With ACFM, the deeper the crack, the larger the response.

The ACFM Walking Stick has passed stringent EMC tests and undergone rigorous laboratory and site trials. The system performance was evaluated by Corus Rail Technologies who compared the ACFM results from 72 Rolling Contact Fatigue (RCF) cracks with destructive analysis and summarised “the capability of detection of the ACFM system has been found to be close to 100%.”


Standard Probes

TSC standard ACFM Walking Stick probes are currently available for plain rail inspection. Features include:

  • Reliable identification and classification of Rolling Contact Fatigue (RCF) cracks
  • Inspection of the whole rail head surface in one pass – gauge side to field side
  • Integral encoder – allows longitudinal position in miles and yards on rail to be recorded

The probe can be used as a primary inspection tool for the detection of the presence of surface breaking cracks in the rail head. It can also be used as a screening tool where cracks already identified by other methods can be inspected and their severity assessed. The ACFM Walking stick is capable of inspecting continuous welded or jointed rail.


The ACFM for Rails software package provides complete Walking Stick instrument control, data collection, storage and analysis. The software package is provided in two parts, the Inspection PC component and the Basestation PC component, for on-track inspection and off-track storage & reporting respectively.

ACFM for Rails software had been developed to run on portable and desktop PC’s running Microsoft Windows XP/2000/NT/9x.

The ACFM for Rails package provides an easy to use large-button interface particularly suited for portable PC’s with touch screens, whilst retaining familiar windows menus if preferred.

The following software package is available for the rail inspection:

ACFM for Rails

The following components comprise the standard software package:

  • Inspection PC
Runs on a small-form ruggedised PC integrated into the Walking Stick frame. Performs data collection and automated audible and visual defect analysis.
  • BaseStation PC
Typically a trackside laptop PC or office-based PC. Provides long term data storage, summary reports and post-inspection auditing and analysis.