There are two basic ways to unload coal from a rail car at the power plant: rotary dump or bottom dump. (A third option, side dump, generally is applicable only for specialized short-haul situations.) Where rotary dumping is used, cars are equipped with rotary couplers so they may be turned over without uncoupling or breaking an air line. The standard cross-dump hopper has poor characteristics for rapid unloading. To bottom-dump coal efficiently while in motion, unit trains require a mechanized self-clearing, quick-dumping car - one that unloads in a matter of seconds - controlled automatically or semiautomatically. This demands a large bottom opening - either large doors or many doors - and usually a pneumatic- or electropneumatic- actuated door-opening and -closing system. Quick-dump cars also are more expensive than standard gondolas or hoppers. A fundamental step in selecting a coal-unloading system is to determine the cost of bottom-dump facilities and compare it to the price of a fleet of solid-bottom gondolas plus a rotary car-dumper. In short-haul situations, the more-rapid unloading of quick-dump cars may reduce the cycle time enough to save an entire unit train. The saving in time gained by using quick-dump cars may represent a significant dollar saving to the delivering railroad in terms of train-crew costs. Total operating cost for a rotary-car dumping system is likely to be less than the additional car-maintenance cost associated with the doors and actuating mechanisms of quick-dump cars. Finally, a rotary-dumper installation has the advantage of being entirely enclosed. Thus, control of dust is simplified. This could be important in the case of unwashed coal.

  • Availability:
  • Corporate Authors:

    McGraw-Hill, Incorporated

    330 West 42nd Street
    New York, NY  United States  10036
  • Publication Date: 1975-8

Media Info

  • Pagination: p. 47
  • Serial:
    • Power
    • Volume: 119
    • Issue Number: 8
    • ISSN: 0032-5929

Subject/Index Terms

Filing Info

  • Accession Number: 00128857
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Feb 4 1976 12:00AM