Types Classification yard

1 types

1.1 flat yard
1.2 hump yard
1.3 gravity yard

types
flat yard

flat yards constructed on flat ground, or on gentle slope. freight cars pushed locomotive , coast required location.

cnw towerman r. w. mayberry operates retarders @ proviso yard in chicago, illinois, may 1943.


hump yard

not cars can sent on classification hump. union pacific track maintenance vehicle permanently labelled not hump , because not designed withstand hump sorting.

hump yards largest , effective classification yards, largest shunting capacity, several thousand cars day. heart of these yards hump—a lead track on small hill on engine pushes cars. single cars, or block of coupled cars, uncoupled before or @ crest of hump, , roll gravity onto destination tracks in tracks cars sorted, called classification bowl.

the speed of cars rolling down hump classification bowl must regulated according whether full or empty, heavy or light freight, varying number of axles, whether there few or many cars on classification tracks, , varying weather conditions, including temperature, wind speed , direction. concerns speed regulation, there 2 types of hump yards—without or mechanisation retarders. in old non-retarder yards braking done in europe railroaders laid skates onto tracks. skate or wheel chock manually (or, in rare cases, mechanically) placed on 1 or both of rails treadles or rims of wheel or wheels caused frictional retardation , resulted in halting of railway car. in united states braking done riders on cars. in modern retarder yards work done mechanized rail brakes called retarders, brake cars gripping wheels. operated either pneumatically or hydraulically. pneumatic systems prevalent in united states, france, belgium, russia , china, while hydraulic systems used in germany, italy , netherlands.

classification bowls in europe typically consist of 20 40 tracks, divided several fans or balloons of tracks, 8 classification tracks following retarder in each one, 32 tracks altogether. in united states, many classification bowls have more 40 tracks - divided 6 ten classification tracks in each balloon loop.

bailey yard in north platte, nebraska, united states, world s largest classification yard, hump yard. other large american hump yards include argentine yard in kansas city, kansas, second-largest in world, robert young yard in elkhart, indiana, clearing yard in chicago, illinois, englewood yard in houston, texas, , waycross rice yard in waycross, georgia. notably, in europe, russia , china, major classification yards hump yards. europe s largest hump yard of maschen near hamburg, germany; smaller bailey yard. second largest in port of antwerp, belgium. hump yards single yards 1 classification bowl, some, large, hump yards have 2 of them, 1 each direction, double yards, such maschen, antwerp, clearing, , bailey yards. according prrt&hs prr chronology, first hump yard in united states opened may 11, 1903 part of altoona yards @ bells mills (east altoona). other sources report prr yard @ youngwood, pa opened in 1880s serve connellsville coke fields first u.s. hump yard.

gravity yard

gravity yards operated hump yards but, in contrast latter, whole yard set on continuous falling gradient. when invented in 19th century, saving shunting engines , instead letting cars roll gravity seen major benefit, whereas larger amount of manual work required stop rolling cars in classification tracks judged not important. gravity yards historical step in development of classification yards , later judged inferior hump yards, because became clear shunting engines needed anyway (at least in inclement weather strong winds or icy temperatures when oil in bearings became thick), , because manual labour getting relatively more , more expensive. thus, few gravity yards ever built, requiring massive earthwork (one example first german gravity yard @ dresden).

most gravity yards built in germany , great britain, few in other european countries, example Łazy yard near zawiercie on warsaw-vienna railway (in poland). in usa, there few old gravity yards; 1 of few gravity yards in operation today csx s readville yard south of boston, massachusetts.

almost gravity yards have been retrofitted humps , worked hump yards. examples include dresden friedrichstadt , nürnberg (nuremberg) rbf (rbf: rangierbahnhof, classification yard ), both in germany.