DETECTING THE PROPAGATION OF KIDNEY-SHAPED FATIGUE FLAWS IN RAIL HEADS ON THE LINES OF THE HUNGARIAN STATE RAILWAYS

The author discusses the cause and propagation of kidney-shaped fatigue flaws in the rail head as well as the measures designed to prevent fractures. The main purpose is the description of the functional relationship between the propagation of the fatigue flaw and the traffic load. The formation of flakes in the rail material, the hardness of the rail head and the notch effect set up in the rail head by internal flaws are discussed. It is found that the propagation of the flaws is jointly caused by a number of processes such as microinclusions, oscillatory movements of dislocations, high stresses in the rail head, etc. The positions of the initial centres have been investigated by examining and measuring several fractures. Methods for calculating the height of the fissure and its inclination towards the vertical are developed. An analysis is made of the development of fatigue flaws as a function of the traffic load, and the existing relationship is established by an equation. In determining the effective cross-sectional area of the rail, the wear of the rail is also taken into account and added to the area of the fatigue flaw. After an analysis of the permissible threshold values, certain specifications are suggested, and the size of the flaw area in percent of the total cross-sectional area of the rail head is indicated with the aid of nomographs. In addition to the manual examinations, the introduction of ultrasonic high-speed testing vehicles is urgently recommended. In modern railway operation, ultrasonic testing is the most suitable method of detecting dangerous flaws; but the influence of human subjectivity in evaluating the results must be eliminated by using modern computers.

• Corporate Authors:

  International Railway Congress Association

  17-21 rue de Louvrain
  1000 Brussels,   Belgium 
• Authors:
  • Kecskes, O S
• Publication Date: 1972-9

Media Info

• Features: Figures; References;
• Pagination: p. 493-506
• Serial:
  • RAIL INTERNATIONAL
  • Volume: 3
  • Issue Number: 9

Subject/Index Terms

• TRT Terms: Defects; Detection and identification; Railhead; Railroad rails; Stresses; Ultrasonic tests; Wear
• Identifier Terms: Magyar Allamvasutak
• Uncontrolled Terms: Rail flaw detection
• Old TRIS Terms: Rail flaw propagation; Rail stress
• Subject Areas: Railroads;

Filing Info

• Accession Number: 00046362
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 4 1976 12:00AM