This report should be of interest to engineers involved in the design, construction, and maintenance of direct-fixation track systems, a subset of non-ballasted track systems. The two-part report provides guidance on the design and construction of direct- fixation track systems. Part A includes sections describing track-design principles and material-evaluation methods for direct-fixation fasteners and track, as well as example specifications and commentary for direct-fixation fasteners, direct-fixation fastener qualification and production tests, direct-fixation track construction, and materials used in direct-fixation applications. The purpose of the commentary provided with the example specifications is to explain the basis for specification stipulations, the relevance of stipulations in various applications, and key issues and trade-offs that must be made in developing specifications for the design and construction of direct-fixation track systems. Part B of the report provides data, evaluations, field reviews, and analyses of direct-fixation fasteners from a variety of sources to understand their characteristics and proper application more fully. (Author/publisher)
Samenvatting