Editing Rail yard (section)

==Freight yards ==
For [[freight car]]s, the overall yard layout is typically designed around a principal ''switching'' (US term) or ''shunting'' (UK) technique:
* A flat yard has no hump, and relies on locomotives for all car movements.
* A gravity yard is built on a natural slope and relies less on locomotives; generally locomotives will control a consist being sorted from uphill of the cars about to be sorted. They are decoupled and let to accelerate into the classification equipment lower down.
* A hump yard has a constructed hill, over which freight cars are shoved by yard locomotives, and then gravity is used to propel the cars to various sorting tracks;
 
===Sorting yard basics ===
{{Main|Classification yard}}

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.
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* Switching yards, staging yards, or shunting yards are typically graded to be flat yards, where switch engines manually shuffle and maneuver cars from (a) train arrival tracks, to (b) to consist breakdown track, to (c) an consist assembly track, thence to (d) departure tracks of the yard.
** A large sub-group of such yards are known as staging yards, which are yards serving an end destination that is also a collection yard starting car groups for departure. These seemingly incompatible tasks are because the operating or road company and its locomotive drops off empties and picks up full cars waiting departure which have been spotted and assembled by local switch engines. The long haul carrier makes the round trip with a minimal turn around time, and the local switch engine transfers empties to the loading yard when the industries output is ready to be shipped.
** This activity is duplicated in a transfer yard, the difference being in the latter several industrial customers are serviced by the local switcher, which is part of the yard equipment, and the industry pays a cargo transfer fee to the railroad or yard operating company. In the staging yard, the locomotive is most likely operated by industry (refinery, chemical company or coal mine personnel); and ownership of the yard in both cases is a matter of business, and could be any imaginable combination. Ownership and operation are quite often a matter of leases and interests.{{Efn|The [[Lehigh and Susquehanna Railroad]] was builder and operator of [[Mountain Top Yard]], whereas both were leased to the CNJ, rents and ownership being retained by the [[Lehigh Coal & Navigation Company]].{{Citation needed|date=April 2023}}}}
[[File:Vaganyfek Ferencvaros.JPG|thumb|The "hump" of a hump yard. Railcars travel past retarders, which control their speed, and are directed onto tracks to be assembled into new trains. The control tower operates the retarders.]]
* Hump yards and gravity yards are usually highly automated and designed for the efficient break-down, sorting, and recombining of freight into consists, so they are equipped with mechanical [[Retarder (railroad)|retarders]] (external brakes) and [[Truck scale#Rail weighbridge|scales]] that a computer or operator uses along with knowledge of the [[gradient]] of the hump to calculate and control the speed of the cars as they roll downhill to their destination tracks. These modern sorting and classification systems are sophisticated enough to allow a first car to roll to a stop near the end of its classification track, and, by slowing the speed of subsequent cars down the hump, shorten the distance for the following series of cars so they can bump and couple gently, without damaging one another. Since overall throughput speed matters, many have small pneumatic, hydraulic or spring-driven braking retarders (below, right) to adjust and slow speed both before and after yard switch points. Along with car tracking and load tracking to destination technologies such as RFID, long trains can be broken down and reconfigured in transfer yards or operations in remarkable time.{{citation needed|date=March 2024}}