No abstract

For about 150 years, the steel rail has been at the very heart of the world's railway systems. The rail works in a harsh environment and, as part of the track structure, it has little redundancy; thus, its failure may lead to catastrophic derailment of vehicles, the consequences of which can include death, injury, costs and loss of public confidence. These can have devastating and long‐lasting effects on the industry. Despite the advances being made in railway permanent way engineering, inspection and rail‐making technology, continually increasing service demands have resulted in rail failure continuing to be a substantial economic burden and a threat to the safe operation of virtually every railway in the world. This paper presents an overview of rail defects and their consequences from the earliest days of railways to the present day.

Rail corrugation is a phenomenon of great diversity but appears now to be substantially understood. This review proposes some differences in classification of the phenomenon to take account of work undertaken since a widely cited review was published by Grassie and Kalousek in 1993, it attempts to fill holes in an overall understanding of the problem, and answers questions that remained open in 1993 and several that have arisen since. All types of corrugation that have been documented to date are essentially constant-frequency phenomena. By treating the vehicle-track system in its entirety, treatments are proposed that impinge upon track and vehicle design as well as upon the wheel-rail interface where corrugation appears. There is no neat solution to rail corrugation, but it can be treated comprehensively and in many cases also prevented by using products that are already commercially available. Since the frequency of common wavelength-fixing mechanisms varies roughly in the range 50-1200 Hz, trains travelling at different speeds can produce corrugation of substantially similar wavelength by different mechanisms in different locations. Although historical data can no longer be checked, this is the most likely explanation of the belief that rail corrugation was a substantially constant-wavelength phenomenon.

Two new dynamic models of railway track are presented, one continuous and the other incorporating the discrete mass of the sleepers. These models include the effect of the railpads which exist between rail and sleeper on modern track, and are used to calculate both the response of the track alone and the contact force between a moving wheel and the rail. There is good agreement between calculation and experiment in the frequency range from 50 to 1500 Hz, and it is shown that the railpad is of fundamental importance in attenuating dynamic loads in this frequency range.

Corrugation is a phenomenon which has excited the interest of railwaymen for more than a century, but for which there often does not appear to be a cure. It has generally been realized that there are in fact different corrugation mechanisms, and that some types of corrugation can indeed be prevented. The present paper draws upon both the literature and the authors' experience to categorize corrugation according to two mechanisms: that damaging the rail (wear, plastic flow etc.) and that fixing the corrugation wavelength. Six types of corrugation are thus identified and described by the following proposed terminology: ‘heavy haul’, ‘light rail’, ‘ooted sleeper’, ‘contact fatigue’, ‘rutting’ and ‘roaring rails’. Both mechanisms are well understood for all but the last type of corrugation, for which a convincing and well-validated wavelength-fixing mechanism has yet to be demonstrated. Despite the absence of this understanding, satisfactory treatments of, and in many cases also means of preventing, all six types of corrugation have in fact been developed. Excitation of the vehicle's unsprung mass on the track stiffness is the most common wavelength-fixing mechanism.