Abstracts: NDT of Railway

NDTnet 1998 July, Vol.3 No.7

NDT of Railway

METADEX Antwortnummer 20 - © 1998 CSA
Title
	Derailment Damage and the Need for NDT.
Author
	Wuoti, T. (Queensland Railways)
Publication Source
	Non-Destructive Testing, Australia (Jan.-Feb. 1991) 28, (1), 10-11, Photomicrographs Conference: 6th Asian Pacific Conference on NDT, Blenheim, New Zealand, 5-9 Mar. 1990 ISSN: 0157-6461
Document Type
	Conference Article
Country of Publication
	Australia
Language
	English
Abstract
	Queensland Railways (QR) have shown that, by maintaining high standards of maintenance, the narrow gauge railway system has been able to progress from transporting 1.6 million gross tonnes of coal/year in 1960, using small steam locomotives, to 70 million gross tonnes in 1990, using the latest 1641 kW electric locomotives. Ultrasonic testing of all rail for internal defects is undertaken regularly, based on the gross tonnes carried. This testing is supplemented by QR rail testers, who carry out routine testing of all new welds and other programmed testing as directed. This programmed testing includes derailment testing. During any derailment there is opportunity for the wheel to travel along the sides of the foot of the rail, impacting on track structures, rail anchors, and randomly on the foot of the rail. This type of damage has been found to be particularly severe in cases where the wheel fractures and moves in on the axle. The ultrasonic testing for derailment damage relies on a 79 deg transducer being scanned along the foot of the rail near the edge for a distance of approx 150 mm in one direction only. This technique will locate, at damaged areas in the rail that appears to be minor, very small shear defects. These "invisible" defects would normally have been allowed to remain in the track, with the result being rapid and unpredictable failures in the future. Despite the success of this procedure, it has not been without problems; fatigue cracking has started in a couple of instances on the impacted surfaces where no cracking could have existed in the initial tests.
Accession Number
	92(2):22-211