Chapter: Civil : Railway Airport Harbour Engineering : Railway Engineering : Track Junctions and Simple Track Layouts

Railway Track Junctions: Three throw Switch

In a three-throw arrangement, two turnouts take off from the same point of a main line track.

Three-throw Switch

In a three-throw arrangement, two turnouts take off from the same point of a main line track. A three-throw switch can have contrary flexure or similar flexure, as shown in Figs 15.4 and 15.5, respectively. Three-throw switches are used in congested goods yards and at entry points to locomotive yards, where there is a great limitation of space.

A three-throw switch has two switches and each switch has two tongue rails placed side by side. There is a combined heel block for both the tongue rails of the switch. The switches can be operated in such a way that movement is possible in three different directions, i.e., straight, to the right, and to the left. Three-throw switches are obsolete now as they may prove to be hazardous, particularly at higher speeds, because the use of double switches may lead to derailments.

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Civil : Railway Airport Harbour Engineering : Railway Engineering : Track Junctions and Simple Track Layouts : Railway Track Junctions: Three throw Switch |