Interface - The Journal of Wheel/Rail Interaction

TTCI TECH OVERVIEW

Meeting the Industry’s Technology Goals (continued)

A prototype automated Wheel/Rail Contact Inspection (WRCI) system was developed to monitor wheel/rail contact conditions in order to determine the need or priority of rail maintenance (see Figure 5). When used on Norfolk Southern and BNSF the WCRI system identified track segments that could cause poor wheel/rail interactions, such as contact toward the field side of the low rail, which can increase the risk of rail rollover derailment, and severe two-point contact, which can induce high gauge-spreading forces.

Improved Rail Flaw Inspection
One of the priorities identified in the AAR’s Technology Road Map is to improve reliability of rail inspection, and reduce the number of broken rail derailments that are associated with them.

“Broken rails continue to be the number one engineering cause of derailments,” said Michael Armstrong, BNSF’s General Director – Maintenance Planning. “With advancements in rail flaw detection, we are now beginning to find defects under shells.”

One of the major tasks accomplished in 2008 was to develop and implement laser-based ultrasonic technology for rail inspection (Urail) in revenue service. Rail flaw simulations showed that there are non-inspectable areas when scanning from the top of the railhead with conventional UT technology. The sound path is influenced by rail wear, rail surface damage and the orientation of the flaw. Detection capability would likely increase if rail was inspected from other locations in addition to the top of the railhead.

A prototype, laser-based ultrasonic inspection system was developed that is capable of inspecting the entire rail section. This system, which is based on triangulation between the laser beam and digital camera, provides real time adjustment of the laser sources and sensors compensate for geometrical changes in the rail section. While the technology is able to detect defects in the rail head, web and base, it generates a high number of false calls. Work is underway to identify and address problem areas.

Efforts such as these ensure that the effects of wheel/rail interaction are solidly represented on the Technology Road Map.

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