trainyard

A classification yard (American English, as well as the Canadian National Railway), marshalling yard (British, Hong Kong, Indian, and Australian English, as well as the Canadian Pacific Railway) or shunting yard (Central Europe) is a railway yard found at some freight train stations, used to separate railway cars onto one of several tracks. First the cars are taken to a track, sometimes called a lead or a drill. From there the cars are sent through a series of switches called a ladder onto the classification tracks. Larger yards tend to put the lead on an artificially built hill called a hump to use the force of gravity to propel the cars through the ladder.
Freight trains that consist of isolated cars must be made into trains and divided according to their destinations. Thus the cars must be shunted several times along their route in contrast to a unit train, which carries, for example, automobiles from the plant to a port, or coal from a mine to the power plant. This shunting is done partly at the starting and final destinations and partly (for long-distance-hauling) in classification yards.

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