Rail profile

March 8, 2010

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Delivery Lead Time: Two Weeks ( keyword: hole-free crystallized glass panel no pore crystallized glass minicrystal stone micro crystal glass crystal glass marble sculpture artificial stone marble construction material super white crystal white pure white jade white <>Rail from 1896Cross-sections of flat-bottomed which can rest directly on the sleepers, and bullhead rails which sit in chairs (not shown).A rail profile is a hot rolled steel profile of a specific shape or cross section (an asymmetrical I-beam) designed for use as the fundamental component of railway track.Unlike some other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high quality steel. It took many decades to improve the quality of the materials, including the change from iron to steel. Minor flaws in the steel that pose no problems in reinforcing rods for buildings, can, however, lead to broken rails and dangerous derailments when used on railway tracks.By and large, the heavier the rails and the rest of the trackwork, the heavier and faster the trains these tracks can carry.The rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by the steelworks at the one time, so a railway must choose the nearest suitable size. Worn, heavy rail from a mainline is often reclaimed and downgraded for re-use on a branchline, siding or yard.Rail sizesTwo different rail profiles commonly used by the Belgian Railways: an already used 50 kg-profile (left) next to a new 60 kg-profilePound is a railroad term that indicates the weight of rail per yard. For example one yard of “132 pound rail” weighs 132 pounds. Depending on the use of imperial or metric units, rail sizes are usually expressed in terms of pounds per yard or kilograms per metre. Coincidentally, the pounds-per-yard figure is almost exactly double the kilograms-per-metre figure, making rough conversions easy. Rails in Canada, the United Kingdom, and United States are still described using imperial units. However, in Australia they are now described in metric units and always have been on mainland Europe.EuropeRails are made in a large number of different sizes. Some common European rail sizes include:40kg/m (81 lb/yd) 50kg/m (101 lb/yd) 54kg/m (109 lb/yd) 60kg/m (121 lb/yd) In the countries of former USSR 65kg/m (130lb/yd) rails are common. Thermally hardened 75kg/m (150lb/yd) rails also have been used on heavy-duty railroads like Baikal-Amur Mainline, but have proven themselves deficient in operation and were mainly rejected in favor of 65kg/m (130lb/yd) rails.North AmericaWeight mark on a jointed segment of 155 pound “Pennsylvania Special” rail. The heaviest grade of rail ever mass produced.The American Society of Civil Engineers (or ASCE) specified rail profiles in 1893 for 5-pound-per-yard (2.5kg/m) increments from 40 to 100 pounds per yard (20 to 50kg/m). Height of rail equaled width of foot for each ASCE tee-rail weight; and the profiles specified fixed proportion of weight in head, web and foot of 42%, 21% and 37%, respectively. ASCE 90-pound-per-yard (45kg/m) profile was adequate; but heavier weights were less satisfactory. In 1909 the American Railway Association (or ARA) specified standard profiles for 10-pound-per-yard (5.0kg/m) increments from 60 to 100 pounds per yard (30 to 50kg/m). The American Railway Engineering Association (or AREA) specified standard profiles for 100, 110 and 120 pound rails in 1919, for 130 and 140 pound rails in 1920, and for 150 pound rails in 1924. The trend was to increase rail height/foot-width ratio and strengthen the web. Disadvantages of the narrower foot were overcome through use of tie-plates. AREA recommendations reduced the relative weight of rail head down to 36%, while alternative profiles reduced head weight to 33% in heavier weight rails. Attention was also focused on improved fillet radii to reduce stress concentration at the web junction with the head. AREA recommended the ARA 90 pound profile. Old ASCE rails of lighter weight remained in use, and satisfied the limited demand for light rail for a few decades. AREA merged into the American Railway Engineering and Maintenance-of-Way Association in 1997. By the mid-20th century, most rail production was medium heavy (112 to 119 pound) and heavy (127 to 140 pound.) Sizes under 100 pound rail are usually for lighter duty freight, low use trackage, or light rail. Track using 100 to 120 pound rail is for lower speed freight branch lines or rapid transit (for example, most of the New York City Subway system track is constructed with 100 pound rail). Main line track is usually built with 130 pound rail or heavier. Some common North American rail sizes…(and so on) To get More information , you can visit some products about , . The super white crystallized glass panel ( no pore) products should be show more here! 


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