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A rail fastening system is a means of fixing rails to railroad ties (North America) or sleepers (British Isles, Australasia, and Africa). The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system.
A railroad tie, crosstie (American English), railway tie (Canadian English) or railway sleeper (Australian and British English) is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade , hold the rails upright and keep them spaced to the correct ...
Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. [1] No moments are transferred throughout the support, hence their structural type is known as simply supported. The simplest beam bridge could be a log (see log bridge), a wood plank, or a stone slab (see clapper bridge) laid
Heavier rail can support greater axle loads and higher train speeds without sustaining damage than lighter rail, but at a greater cost. In North America and the United Kingdom, rail is graded in pounds per yard (usually shown as pound or lb), so 130-pound rail would weigh 130 lb/yd (64 kg/m). The usual range is 115 to 141 lb/yd (57 to 70 kg/m).
It was an expensive method of laying track as heavy cast iron chairs were needed to support the rail, which was secured in the chairs by wooden (later steel) wedges or "keys", which required regular attention. Bullhead rail was the standard for the British railway system from the mid-19th until the mid-20th century.
The track consists of steel rail resting on concrete supports via rubberised cork absorption pads with galvanised steel tie beams which wrap around the concrete members rather than being cast into the concrete as with other ladder tracks. The track is modular and precast, rather than being cast in situ. Modular turnouts are also produced. [7]
In a plate girder bridge, the plate girders are typically I-beams made up from separate structural steel plates (rather than rolled as a single cross-section), which are welded or, in older bridges, bolted or riveted together to form the vertical web and horizontal flanges of the beam. In some cases, the plate girders may be formed in a Z-shape ...
Timber sleepers, that is transverse beams supporting the two rails that form the track, replaced the individual stone blocks formerly used. This system has the major advantage that maintenance adjustments to the track geometry did not disrupt the all-important track gauge. The alignment of the track could be adjusted by shifting the sleepers ...