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Classification yard
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<h2 id="flat">Flat</h2> <p>Flat yards are constructed on ground too flat to allow a free-fall operation. After a push by a locomotive, freight cars coast to their desired location.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> </p> <h2 id="gravity">Gravity</h2> <p>Gravity yards were invented in the 19th century, saving shunting engines and instead letting the cars roll by gravity was seen as a major benefit, whereas the larger amount of manual work required to stop the rolling cars in the classification tracks was judged to be not that important. Gravity yards were a historical step in the development of classification yards. They were later judged as inferior to hump yards because it became clear that shunting engines were needed anyway (at least in inclement weather like strong winds or icy temperatures when the oil in the bearings became thick) and because manual labor was getting relatively more and more expensive. Thus, only a few gravity yards were ever built, sometimes requiring massive earthwork (one example is the first German gravity yard at Dresden). The historic technique of a gravity yard is today partly presented in <a href="/facts/Chemnitz/C1z9UDBq">Chemnitz</a>-Hilbersdorf gravity yard (museum).<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> </p><p>Most gravity yards were built in Germany (especially in the kingdom of <a href="/facts/Saxony/PrKscwCP">Saxony</a>) and Great Britain (such as Edgehill, 1873),<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> a few also in some other European countries, for example <a href="/facts/%C5%81azy/WLvKmb3I">Łazy</a> yard near <a href="/facts/Zawiercie/K1tIXk34">Zawiercie</a> on the <a href="/facts/Warsaw%E2%80%93Vienna_railway/sYwdnmP8">Warsaw–Vienna Railway</a> (in <a href="/facts/Poland/eXJ7fd0D">Poland</a>). In the US, there were very few old gravity yards; one of the few gravity yards in operation today is CSX's <a href="/facts/Readville_(MBTA_station)/Icsh8Iz8">Readville Yard</a> south of <a href="/facts/Boston,_Massachusetts/exjfn6xf">Boston, Massachusetts</a>. </p> <h2 id="hump">Hump</h2> <p>Hump yards are the largest and most effective classification yards, with the largest <a href="/facts/Shunting_(rail)/hPPGKvtM">shunting</a> capacity, often several thousand cars a day. They work similarly to gravity yards, but the falling gradient is limited to a small part of the yard, namely the hump. It is the heart of the yard—a lead track on a small hill over which an engine pushes the cars. Single cars, or a block of coupled cars, are uncoupled at or just before the crest of the hump and roll by gravity onto their destination tracks in the area of the yard where the cars are sorted, called the classification bowl.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> The first hump in Germany (Leipzig) was built in 1858 and in France (Saint-Etienne) in 1863. </p> <p>The speed of the cars rolling down from the hump into the classification bowl must be regulated according to whether they are full or empty, heavy or light freight, varying number of axles, whether there are few or many cars on the classification tracks, and varying weather conditions, including temperature, wind speed, and direction. In regards to speed regulation, there are two types of hump yards—with or without mechanization by <a href="/facts/Retarder_(railroad)/a6hMuVbM">retarders</a>. In the old non-retarder yards, braking was usually done in Europe by railroaders who laid skates onto the tracks. The skate or <a href="/facts/Wheel_chock/qtF4Qct1">wheel chock</a> was manually (or, in rare cases, mechanically) placed on one or both of the rails so that the treadles or rims of the wheel or wheels caused frictional retardation and resulted in the halting of the railway car. In the United States, riders in cars did this braking. In modern retarder yards, this work is done by mechanized "rail brakes," called retarders, which brake cars by gripping their wheels. They are operated either <a href="/facts/Pneumatics/QzkvCCpk">pneumatically</a> or <a href="/facts/Hydraulics/KSIqLovc">hydraulically</a>. Pneumatic systems are prevalent in the United States, <a href="/facts/France/CxIeIKM3">France</a>, <a href="/facts/Belgium/YKuMXP5j">Belgium</a>, <a href="/facts/Russia/jfkCwyxn">Russia</a> and <a href="/facts/China/lTjIXY5p">China</a>, while hydraulic systems are used in <a href="/facts/Germany/paluuWBX">Germany</a>, <a href="/facts/Italy/tUf0PDYF">Italy</a> and the <a href="/facts/Netherlands/y8xn5stT">Netherlands</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p><p>Classification bowls in Europe typically consist of 20 to 40 tracks, divided into several fans or balloons of tracks, usually with eight classification tracks following a retarder in each one, often 32 tracks altogether. In the United States, many classification bowls have more than 40 tracks, frequently divided into six to ten classification tracks in each balloon loop. </p> <p><a href="/facts/Bailey_Yard/Eccy69YP">Bailey Yard</a> in <a href="/facts/North_Platte,_Nebraska/UwUVvCcW">North Platte, Nebraska</a>, United States, the world's largest classification yard, is a hump yard. Other large American hump yards include Argentine Yard in <a href="/facts/Kansas_City,_Kansas/fhbBWSNT">Kansas City, Kansas</a>, Robert Young Yard in <a href="/facts/Elkhart,_Indiana/YGkjH1gh">Elkhart, Indiana</a>, <a href="/facts/Belt_Railway_of_Chicago/NGMbwD4G">Clearing Yard</a> in <a href="/facts/Chicago/yPMokrXH">Chicago</a>, <a href="/facts/Illinois/MuPb1Ctn">Illinois</a>, Englewood Yard in <a href="/facts/Houston/1v8AwQUN">Houston</a>, <a href="/facts/Texas/B987WHF0">Texas</a>, and Waycross Rice Yard in <a href="/facts/Waycross,_Georgia/fXY7vBk6">Waycross, Georgia</a>. Notably, in Europe, Russia, and China, all major classification yards are hump yards. Europe's largest hump yard is that of <a href="/facts/Maschen_Marshalling_Yard/oehajNRH">Maschen</a> near <a href="/facts/Hamburg/kmAAsYtT">Hamburg</a>, Germany; it is only slightly smaller than Bailey Yard. The second largest is in the port of <a href="/facts/Antwerp/v3Rwa1Mu">Antwerp</a>, Belgium. Most hump yards are single yards with one classification bowl, but some, mostly very large, hump yards have two of them, one for each direction, and thus are double yards, such as the Maschen, Antwerp, Clearing, and Bailey yards. </p><p>Almost all gravity yards have been retrofitted with humps and are worked as hump yards. Examples include <a href="/facts/Chemnitz/C1z9UDBq">Chemnitz</a> Hilbersdorf (today <a href="/facts/Saxon_Railway_Museum/LmsyszXz">Saxon Railway Museum</a>), Dresden Friedrichstadt and Nürnberg (<a href="/facts/Nuremberg/Bht6TsP4">Nuremberg</a>) Rbf (Rbf: <i>Rangierbahnhof</i>, "classification yard"), in Germany. </p> <h2 id="unique-locomotives">Unique locomotives</h2> <p>Hump yards sometimes require unique locomotives; for example, there can be a risk of grounding with larger frames. For this and other reasons, one can sometimes find locomotives specifically made or converted to work a hump yard. For example, the <a href="/facts/British_Rail_Class_13/CtAPb7L8">British Rail Class 13</a> was converted from a pair of <a href="/facts/British_Rail_Class_08/U5uCEKNy">British Rail Class 08</a> to provide more power than one could get with a single Class 08. The class 13s were built because of the risk of grounding with larger locos like the <a href="/facts/British_Rail_Class_20/jeoMREcb">British Rail Class 20</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> Special locomotives for hump yards in the US were for example the EMD TR family (<a href="/facts/EMD_TR/LoHaxz57">EMD TR</a>, <a href="/facts/EMD_TR1/tcCsXfaL">EMD TR1</a>, <a href="/facts/EMD_TR2/LoHaxz57">EMD TR2</a>, <a href="/facts/EMD_TR3/LoHaxz57">EMD TR3</a>, <a href="/facts/EMD_TR4/Nge2gaJd">EMD TR4</a>, <a href="/facts/EMD_TR5/0UxcRdww">EMD TR5</a> and <a href="/facts/EMD_TR6/Mr6kuRB5">EMD TR6</a>). These are often referred to as <i><a href="/facts/Cow%E2%80%93calf/U046qEHg">master and slave</a></i> in GB and <i>cow–calf</i> in the US.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h2 id="image-gallery">Image gallery</h2> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/List_of_rail_yards/jq5NwhPp">List of rail yards</a></li> <li><a href="/facts/Siding_(rail)/kVc7HpEl">Siding (rail)</a></li></ul> <h2 id="further-reading">Further reading</h2> <ul><li>International Railway Journal (IRJ), New York. <i>Special editions about hump yards in various countries:</i> issues II/66, II/70, VI/75, II/80.</li> <li>Armstrong, John H. (1998). <i>The Railroad: What It Is, What It Does</i> (4th ed.). Omaha, Nebraska: Simmons-Boardman. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-911382-04-4.</li> <li>Rhodes, Michael: <i>The Illustrated History of British Marshalling Yards.</i> Sparkford: Haynes Oxford Publishing & Co, 1988. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-86093-367-9. Out of print.</li> <li>Kraft, Edwin: <i>The Yard: Railroading's Hidden Half.</i> In: <a href="/facts/Trains_(magazine)/MlA2y9Qr">Trains</a> (vol. 62) 2002. Part I: VI/02, pp. 46–67; Part II: VII/02, pp. 36–47. <a href="/facts/ISSN_(identifier)/DPAflDvU">ISSN</a> <a href="https://www.worldcat.org/search?fq=x0:jrnl&q=n2:0041-0934">0041-0934</a>.</li> <li>Wegner, Robert: <i>Classification yards. Map of the Month.</i> In: Trains IV/2003, pp. 42–43.</li> <li>Rhodes, Michael: <i>North American Railyards.</i> St. Paul (US): Motorbooks International (MBI Publishing Company) 2003. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-7603-1578-7.</li></ul> <h2 id="external-links">External links</h2> Wikimedia Commons has media related to Classification yards. <ul><li><a href="https://www.youtube.com/watch?v=6nz-n49pIFQ">Time-lapse video of German hump-shunting yard operation</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>James T. Kneafsey (1975). "Major Problems of Railroad Service". Transportation Economic Analysis. Lexington Books. p. 138. ISBN 0669932116. <a href="0669932116" target="_blank">0669932116</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Denkmalpflege in Sachsen, Jahrbuch 2019, Sandsteinverlag, Dresden, 2020. <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Köpcke, Mitteilungen (1890). aus dem Bereich des englischen Eisenbahnwesens. Leipzig: Der Civilingenieur. <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>"ABC's of Railroading: Terms of the Trade". Trains. Waukesha, Wisconsin: Kalmbach Publishing. June 1991. p. 22. ISSN 0041-0934. <a href="/wiki/Trains_(magazine)" target="_blank">/wiki/Trains_(magazine)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Rangierdienst A-Z. Berlin: VEB Transpress-Verlag. 1986. <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Bickerdyke, Paul, ed. (October 2015). "Class 13 Tinsley Shunters". Rail Express. No. 233. Horncastle: Mortons Media Publishing. p. 25. ISSN 1362-234X. <a href="/wiki/ISSN_(identifier)" target="_blank">/wiki/ISSN_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Solomon, Brian; Blaszak, Michael; Gruber, John; Guss, Chris (2014-10-14). Chicago: America's Railroad Capital: The Illustrated History, 1836 to Today. Voyageur Press. p. 37. ISBN 978-0-7603-4603-7. <a href="978-0-7603-4603-7" target="_blank">978-0-7603-4603-7</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Foster, Gerald L. (1996). A Field Guide to Trains of North America. Houghton Mifflin Harcourt. p. 10. ISBN 978-0-395-70112-6. <a href="978-0-395-70112-6" target="_blank">978-0-395-70112-6</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Smith, Keith (1999). Supplement to the West Somerset Railway Stockbook (5th ed.). Bishops Lydeard: West Somerset Railway Association. p. 9. <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Industrial Locomotives (6EL ed.). Industrial Railway Society. 1982. p. 232. ISBN 0-901096-44-X. <a href="0-901096-44-X" target="_blank">0-901096-44-X</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> </ol>