World's First Digital Recording Field Gradient Camera

Pedestrian Rail Inspection System

· Gauge Corner Cracking · Head Checking · Rolling Contact Fatigue · Squat · Real Time Imaging Camera and Trolley · Digital Archiving (Data & Text) · Database Software for PC review and storage · Colour Palette defect severity and visualisation ·

With support from DTI and a major UK infrastructure owner, Newt International Limited have made the dream reality.

Non-contacting FG Camera and interface electronics (sees through up to 4mm of dirt, oil, etc.), with a target defect sensitivity of 5mm long by 1mm deep. LCD display with rolling colour Imaging of rail defect position and severity. Colour palette selection for severity. Text input for reference and close visual comments. Complete digital rail inspection data archiving. Data port interface for file transfer to desktop/laptop PCs for post acquisition data analysis and file archiving. LIZARD® database software for archiving, 3rd party review and maintenance planning. Optional modem for direct Intranet transfer. System based upon P.C architecture Battery operated EN473 operator courses

For further information regarding price and delivery please contact sales@lizard.co.uk

Comparison of Field Gradient Camera and Ultrasonics

This is a planar scan of a 70cm section of rail taken from a UT negative site.

The gray band aligns with the rail corner, the other colours represent a series of contours where white represents a crack depth of 10mm or greater. You can see the beautiful image of individual cracks transverse to the rail, giving both their direction and severity. Now we have the problem why doesn't ultrasonic see these?

Ultrasonic as per procedure of 75cm of section of rail from a UT negative site.

The small wriggles in noise represent the best Ultrasonic could do, you can see you have a good rail bottom return and the horizontal 100% line is marked. The cracks were not immediately visible.

For these defects to be detectable using ultrasonic procedures currently employed in the Rail infrastructure industry they have to be present at an angle, which reflects the incident ultrasonic wave back to the detector. However, the morphology of the defects makes it unlikely that they will fall into the detector's range of acceptance. Defect orientation can be from fully transverse to longitudinal transverse and any planar position between these. There are demonstrably different modes of defect initiation and growth between high strain, low cycle and low strain, high cycle fatigue (heavy haul and fast passenger traffic).

The photograph of a sectioned rail, containing Gauge Corner Cracks, shows large defects "bleeding" red dye, yet because these are orientated at the "wrong" angle they remain invisible to standard rail ultrasonic techniques.

The field gradient technique is particularly able to address these defects and has been the subject of targeted development on behalf of the UK rail industry and DTI, receiving awards from industry and Government. It is an ideal tool for the early detection of Gauge Corner Cracking. Therefore, defects could be targeted at a non-critical stage in rail refurbishment/replacement programmes.

We believe that Newt International Limited have got a winner in this particular application for the Field Gradient Camera.

For further information regarding price and delivery please contact sales@lizard.co.uk

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