Railway Use
On railways, a given section of track is designed to a maximum axle load. The maximum axle load is related to the strength of the track, which is determined by weight of rails, density of sleepers and fixtures, train speeds, amount of ballast, and strength of bridges. Because track and especially the rails are expensive, it is desirable to optimise the track for a given axle load. If the track is overloaded by trains that are too heavy, it can be destroyed in a short time. It is convenient for the steelworks that rails are made in a limited number of sizes, so that a perfect match of rail weight and axle load is rarely achieved. New rail is often reserved for heavy main line use, which releases good but lighter rail that can be cascaded for lighter duties on branch lines. The lightest rail cascaded from the lightest branch lines may have no railway use other that for structural items such as fenceposts, telegraph posts and for reinforcing concrete. Increase density of sleepers and reduce axle load can help to increase train speeds.
Read more about this topic: Axle Load
Famous quotes containing the word railway:
“Her personality had an architectonic quality; I think of her when I see some of the great London railway termini, especially St. Pancras, with its soot and turrets, and she overshadowed her own daughters, whom she did not understand—my mother, who liked things to be nice; my dotty aunt. But my mother had not the strength to put even some physical distance between them, let alone keep the old monster at emotional arm’s length.”
—Angela Carter (1940–1992)