Towers, Contact System

reinforced-concrete, metal, or wooden structures that carry the overhead suspension and other overhead wires on electric railroads. The overhead suspension is fastened to the towers by overhanging end brackets, rigid metal crossbars, or a system of transverse cables; other overhead wires are fastened to the towers by wooden or metal cantilevers.

The towers of an overhead contact system are categorized, according to their functions, as support towers (intermediate or transition towers), anchor towers (those subjected to tension loading from the wires), locater towers (those that position the conductors with respect to the trolley axis of the rolling stock), and feeder towers (used to suspend feeder and outlet lines). As to their design, the towers can be either freestanding or guyed. On one- and two-track railroad lines and isolated sections near railroad stations, overhanging towers are used.

The type of tower most widely used in the USSR is the conical reinforced-concrete tower. Such towers are either bedded directly in the soil or installed on footings, depending on hydrological conditions and on the type of current being carried by the contact system. Metal towers with flexible crossarms are installed in stations with more than eight to ten tracks; they are also used as anchor towers in cases where the use of guyed reinforced-concrete towers is not possible. Metal towers for feeder lines are mounted on block- or pile-shaped reinforced-concrete footings. Wooden towers for overhead contact systems are used only as temporary structures.