Performance Characteristics for Wood Tie Fasteners
Date
1984-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
American Railway Engineering Association
Abstract
As railroad freight axle loads and train weights have increased, there has emerged growing concern as to the adequacy of conventional cut spike fasteners for wood tie track. This concern, coupled with the advent of a new generation of wood tie fasteners, has led to a requirement for the development of performance characteristics for wood tie fasteners under present heavy axle load railroad conditions. Over the years, the performance of cross-tie fastener systems has been the subject of numerous analyses, investigations and testing. From these investigations have emerged the range of performance characteristics that are required for fasteners under heavy traffic and axle 1oad conditions. These characteristics differ from the European and other lighter axle load applications in that the load environment under which the fastener as well as the ties must perform effectively is significantly more severe in all major areas: vertical loading, lateral load1ng, and longitudinal loading. This is particularly true in many of the North American railroads’ non-conventional fastener applications to date. These have concentrated on the severe curvature territories that had been traditional problem areas for wood ties and cut spike fasteners. These areas in turn are the ones in which the most severe traffic 1oadings are operated and for which the tie and fastening systems must perform effectively. However, even in the high speed passenger applications in North America, the load environment is more severe than that found elsewhere in the world because of distinctly different operating and maintenance characteristics that include the operation of heavy axle load freight cars over passenger tracks. This in turn generates the severe load requirements under which fasteners and ties must perform. In general, fastener characteristics can be divided into several basic categories representing different aspects of fastener (or railroad) operational requirements. These include: Track Strength and related fastener strength properties, operations and maintenance requirements, and cost/benefit issues. The first of these areas, Track Strength, is directly related to the ability of the fastener system to perform under the railroad loading environment into which it is installed. For North American freight applications, this usually means severe curvature, heavy axle load operations. The next area, operations and maintenance requirements, relates to the practica1 considerations that make for effective track systems because they promote ease of application and matching of fastener- properties and life with the remainder of the track system. The last area, cost/benefit issues, while outside the scope of this paper, can never be avoided in the private North American railroad environment. The benefits that are obtained by the use of an appropriate fastener system must be evaluated in conjunction with their costs. However, it should be noted that life cycle costs of the system must be evaluated, rather than either first costs or isolated component costs. It is the purpose of this paper to concentrate on the performance requirements of fastener systems in track from the point of view of examining the role of and the requirements for the fastening system. It is not the intention of this paper to define performance specifications or performance tests, but rather to look at the role of the fastener in the railroad track structure and examine its operating environment, and the functions that it serves. It is left to the operating railroads themselves to extend these performance characteristics and to define specifications from these characteristics based on the specific requirements and circumstances of the railroad. Specifications such as those developed by the American Railway Engineering Association are designed to help guide the railroad in this area of specifications and specification testing.
Description
Keywords
Wood tie fasteners
Citation
Zarembski, A. M., “Performance Characteristics for Wood Tie Fasteners”, Bulletin of the American Railway Engineering Association, Bulletin 697, Volume 85, October 1984, p.p. 341-369.