Railroad tank cars are one of the principal methods for bulk transport of liquids and liquified gases. The public demands that these cars operate without endangering the safety of individuals, without adverse effect on the environment, and with minimum disruption to the communities through which they travel. In order to meet the public's expectations, tank cars carrying chemical and hazardous liquids must be structurally sound and retain the liquid contents without leakage.

This paper describes development of an acoustic emission based test procedure for in-service railroad tank cars. The cooperative efforts of a number of interested parties including shippers, car builders, owners, repair shops, and consultants contributed to development of the test method. The program built on successful chemical industry experience with fixed tanks and pressure vessels. The resulting procedure, which has been adopted by The Association of American Railroads, is intended to provide a measure of the structural integrity of the tank, bolster, sill, headblock, and interconnecting welds.

Three separate tests are specified in the procedure. A pressure test is used to monitor the integrity of the pressure envelope and attachment welds. A jacking test provides a measure of the integrity of the sill, bolster, and connections to the tank. A twist bar test, in which a torque is applied near the end of the sill, provides an assessment of the structural integrity of the headblock and sill, particularly in the region outboard of the bolster.

Details of the test procedures are reviewed, and the purpose of the key provisions is discussed. The paper also discusses the advantages and disadvantages of the acoustic emission test method, compares it with other methods of nondestructive examination, and describes its complementary role.

Subject
Test methods, Sensors, Yield stress, Acoustic emission, Stress, Filters, Mechanical failure, Defects, Steel, Equipment, Acoustic emission testing, Hydrostatic testing, Stress corrosion cracking
Keywords:
acoustic emission, railroad tank cars, nondestructive examination, pressure test, jacking test, twist bar test
© 1992 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1992
Association for Materials Protection and Performance (AMPP)
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