Weight per meter

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The weight per meter , also called mass coverage or mass coverage, is the length-related weight of a body. Its SI unit is kg / m . It is used to characterize railroad tracks , steel girders or strings .

Anglo-American system of measurement

In the Anglo-American system of measurement , railway tracks are usually given in pounds per yard ( lb / yd ) or in pounds per foot (lb / ft ). A pound per yard is nearly half as heavy as a kilogram per meter ( ).

In railway engineering publications, when characterizing rails, the unit is often shortened to pounds . That is, a " 132-pound rail " weighs 132 pounds per yard.

railway tracks

Usual rail profiles: on the left a heavily worn rail with 50 kg / m and on the right a new rail with 60 kg / m

The weight per meter of railroad tracks is an important factor in determining the maximum permissible load ( load per meter and axle load ) and maximum speed. In simple words; The heavier the splint, the higher the load it can take. However, the heavier a rail, the more difficult it is to install and transport.

In Europe , the following meter weights are common for railroad tracks:

  • 40 kg / m (81 lb / yd)
  • 46 kg / m
  • 50 kg / m (101 lb / yd)
  • 54 kg / m (109 lb / yd)
  • 56 kg / m (113 lb / yd)
  • 60 kg / m (121 lb / yd)

In Switzerland , the installation of rails with 54 kg / m (54 E1 + 54 E2) and 60 kg / m (60 E1 + 60 E2) is common on standard gauge lines for route category D4. The former SBB I profile, i.e. rails with 46 kg / m (46 E1), is mostly only used in train stations and sidings.

The following line weights have been common in the United States since the mid-20th century:

  • Medium heavy: 112 to 119 lb / yd (55.6 to 59.0 kg / m)
  • Heavy: 127 to 140 lb / yd (63.0 to 69.4 kg / m)

Route weights of less than 100 lb / yd (49,6 kg / m) occasionally for little-used routes or light rail said rail vehicles employed. Line weights of 100 to 120 lb / yd (49.6 to 59.5 kg / m) can still be used for slow-moving freight train routes and for subways (e.g. most of the New York subway trains have 100 lb / yd (49.6 kg / m)). Major roads are typically built at 130 lb / yd (64.5 kg / m) or heavier.

Individual evidence

  1. ^ Leonard Church Urquhart: Civil Engineering Handbook, 4th Edition , McGraw-Hill Book Company, 1959.