Portal:Trains/Selected picture/Week 1, 2007

Chicago and North Western Railway towerman R. W. Mayberry operates the retarders at Proviso Yard in Chicago, Illinois, May 1943.

Hump yards are the largest and most effective classification yards with the largest shunting capacity. The heart of these yards is the hump: a lead track on a hill (hump) over which the cars are pushed by the engine. Single cars, or some coupled cars in a block, are uncoupled just before or at the crest of the hump and roll by gravity into their destination tracks in the classification bowl (the tracks where the cars are sorted). They are slowed in their descent by retarders that grip the wheels of passing cars to slow them by friction.