Abstract: The construction of railway track using flat bottom rail clipped to cross ties (sleepers) supported on a bed of similarly sized stones (ballast) has changed very little over the last 160 years despite increasing demands for performance of the track with increasing axle loads and speeds. Modern ballasted track needs continuous investment in sophisticated equipment, processes, manpower and skills to maintain track quality, and innovations such as concrete sleepers, elastic fasteners rail pads etc have merely increased the complexity of a simple concept that was born out of the wooden tracks used for wagon ways in the 17th century. This paper explores how alternative track constructions that seek to reduce to a minimum the task of maintaining track geometry by eliminating the ballast layer, might deliver an improved track form for heavy haul railways. A range of ballastless track forms are now available that aim to deliver much more stable track geometry with lower maintenance demand. Despite their construction complexity when compared with conventional track and their generally higher initial cost, an increasing number of such installations are being made worldwide. However, the majority of ballastless track that has so far been installed is in passenger lines (including high speed) or metros and the available systems have not been optimised for freight applications with heavy axle loads. This paper proposes a set of target criteria for an ideal heavy haul track construction and reviews a selection of the range of current ballastless track constructions against these criteria to expose both their strengths and the areas in need of development or improvement. The paper goes on to describe recent advances in embedded rail technology which, combined with advances in structural concrete design and a reassessment of the properties required from the formation beneath the track, have made it possible to deliver low cost, high performance embedded rail concrete track, optimised for heavy haul. This track form can be considered as an affordable alternative to conventional track offering a safer, more reliable, and hence more productive, heavy haul railway.
Publication Year: 2010
Publication Date: 2010-01-01
Language: en
Type: article
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