Hopper car

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Two-bay hopper cars of the Reading Railroad.
Swedish iron ore hopper (mineral wagon), built in 1900.
BOBRN class Hopper cars Freight rakes used by Indian Railways.

A hopper car is a type of railroad freight car used to transport loose bulk commodities such as coal, ore, grain and track ballast.[1][2][3] Two main types of hopper car exist: covered hopper cars, which are equipped with a roof, and open hopper cars, which do not have a roof.

Hopper car to transport track ballast, 750 mm (2 ft 5 12 in) gauge.

This type of car is distinguished from a gondola car in that it has opening doors on the underside or on the sides to discharge its cargo. The development of the hopper car went along with the development of automated handling of such commodities, with automated loading and unloading facilities.

Covered hopper cars are used for bulk cargo such as grain, sugar, and fertilizer that must be protected from exposure to the weather. Open hopper cars are used for commodities such as coal, which can suffer exposure with less detrimental effect. Hopper cars have been used by railways worldwide whenever automated cargo handling has been desired. "Ore jennies" is predominately a term for shorter open hopper cars hauling taconite by the Duluth, Missabe and Iron Range Railway on Minnesota's Iron Range.

Recently in North America the open hopper car has been in a terminal decline due to the advent of the rotary car dumper (which simply inverts the car to unload it, and has become the preferred unloading technology).[citation needed] A rotary dumper permits the use of simpler and more compact (because sloping ends are not required) gondola cars instead of hoppers. Covered hoppers, though, are still in widespread use.

Special hopper trains[edit]

The Coke Express, a unit train of hopper cars loaded with coke, with the words "Coke Express" painted on the sides of the hoppers.

Typical American Freight Car Weights and Wheel Loads[edit]

Common Net Car Loads Gross Car Weights Wheel Loads
short tons long tons tonnes pounds kilograms pounds kilograms
80 71.4 72.6 220,000 100,000 27,500 12,500
100 89.3 90.7 263,000 119,000 32,875 14,912
101 90.2 91.6 268,000 122,000 33,500 15,200
111 99.1 100.7 286,000 130,000 35,750 16,220
125 111.6 113.4 315,000 143,000 39,375 17,860

Increase in wheel loads has important implications for the rail infrastructure needed to accommodate future grain hopper car shipments. The weight of the car is transmitted to the rails and the underlying track structure through these wheel loads. As wheel loads increase, track maintenance expenses increase and the ability of a given rail weight, ballast depth, and tie configuration to handle prolonged rail traffic decreases. Moreover, the ability of a given bridge to handle prolonged rail traffic also decreases as wheel loads increase.[4]

Etymology[edit]

The word "hopper", meaning a "container with a narrow opening at bottom", goes back to the 13th century,[5] and is found in Chaucer's story "The Reeve's Tale" (written late 14th century) in reference to a machine for grinding grain into flour.

See also[edit]

References[edit]

  1. ^ "Covered Hopper Railcars". GATX Corporation. Retrieved 11 September 2012. 
  2. ^ "Small Cube Open-Top Hoppers and Gondolas". GATX Corporation. Retrieved 11 September 2012. 
  3. ^ "Covered Hopper Cars". Chicago Freight Car Leasing Company. Retrieved 11 September 2012. 
  4. ^ John D. Bitzan; Denver D. Tolliver (October 2001). "The Economics of Heavy Hopper Cars". Mountain Plains. Retrieved 2010-08-07. 
  5. ^ Online Etymology dictionary: [1].

External links[edit]