Rail yard
A rail yard, railway yard, railroad yard (US) or simply yard, is a complex series of tracks in a rail network for storing, sorting, or loading and unloading rail vehicles and locomotives. Yards have many tracks in parallel for keeping rolling stock or unused locomotives stored off the main line, so that they do not obstruct the flow of traffic. Cars or wagons are moved around by specially designed yard switchers (US) or shunters, a type of locomotive. Cars or wagons in a yard may be sorted by numerous categories, including railway company, loaded or unloaded, destination, car  type, or whether they need repairs. Yards are normally built where there is a need to store rail vehicles while they are not being loaded or unloaded, or are waiting to be assembled into trains. Large yards may have a tower to control operations. Many yards are located at strategic points on a main line. Main-line yards are often composed of an up yard and a down yard, linked to the associated direction of travel. There are different types of yards, and different parts within a yard, depending on how they are built. Freight yards. For freight cars, the  overall yard layout is typically designed around a principal "switching" (US term) or "shunting" (UK) technique: Sorting yard basics. In the case of all classification or sorting yards, human intelligence plays a primary role in setting a strategy for the "switching operations"; the fewer times coupling operations need to be made and the less distance traveled, the faster the operation, the better the strategy and the sooner the newly configured consist can be joined to its outbound train. Nomenclature and components. A large freight yard may include the following components: Freight yards may have multiple industries adjacent to them where  railroad cars are loaded or unloaded and then stored before they move on to their new destination. Major freight yards in the US include the Bailey Yard in North Platte, Nebraska, operated by Union Pacific Railroad; Conway Yard near Pittsburgh, operated by Norfolk Southern Railway; and the Corwith Yards (Corwith Intermodal Facility) in Chicago, operated by BNSF Railway. Major UK goods yards (freight) include those in Crewe, Reading and Bescot, near Walsall; which are operated by DB Schenker and Freightliner. Coach yards. Coach yards or stabling yards are used for sorting, storing and repairing passenger cars. These yards are located  in metropolitan areas near large stations or terminals. An example of a major US coach yard is Sunnyside Yard in New York City, operated by Amtrak. Those that are principally used for storage, such as the West Side Yard in New York, are called "layup yards" or "stabling yards." Coach yards are commonly flat yards because passenger coaches are heavier than freight carriages, in the unladen state. Major UK coach stabling yards include those in Crewe and Longsight, Manchester, which are operated by various regional train companies.