hump yard[′həmp ‚yärd]
an engineering facility located at classification yards and some railroad freight stations for making up freight trains and marshaling railroad cars according to type and load. Such a facility makes it possible to increase the volume of switching.
A hump yard is an artificially elevated area within a classification yard where the force of gravity is used to move rail cars along a network of marshaling tracks. A typical example consists of an approach section, the top of the hump, and the release area, which branches out into dozens of marshaling tracks. The release section includes high-speed and intermediate slopes, a braking section, and a sloping switching area. A hump yard’s elevation is determined by calculation (usually it is 3.5–5 m) and must be sufficiently high to enable the rail cars to reach the observation point of the marshaling tracks. Accelerating devices are used at some hump yards.
The rolling stock to be marshaled is pushed by a locomotive to the top of the hump (the cars are uncoupled while they are in motion), where individual cars and groups of cars are separated and allowed to coast on to the release point, where they are diverted by switching devices onto marshaling tracks according to their type and load. After each car or group of cars has passed through a switch, the switch is reset for the next car. To maintain a predetermined distance between the cars that have rolled onto various tracks and thus eliminate the danger of one car overtaking another while within the release area, their velocity is regulated by two or three braking sections fitted with clamp-type car retarders or by weight-operated clamp-type retarders. High-volume hump yards are equipped with automatic centralized equipment and automatic speed controls. Signaling, radio communication, and other such techniques are widely used in hump yards. High-volume hump yards can process up to 6,000–7,000 railroad cars per day.
REFERENCESavchenko, I. E., S. V. Zemblinov, and I. I. Strakovskii. Zhelez-nodorozhnye stantsii i uzly, 2nd ed. Moscow, 1967.
K. M. DOBROSEL’SKII