Triangle – Railway Track Junction
The triangle is a junction of a railway track, which are constructed for changing the direction of engines. They require a large area and therefore they are constructed where there is enough land available for their construction.
Turntables are also used to change the direction of engines, but they are very costly. So, if enough area is available, then the construction of triangles is more preferable than turntable installation. The maintenance cost of the triangle is less as compared to that of the turntable.
Generally, a triangle junction consists of three tracks, they are PQ, QS and SP, which are shown in the fig. Usually, PQ and SQ tracks are curved and PS track is straight. But some times all the three tracks are laid on curves as shown in the figure.
A dead-end siding QR is provided at point Q to accommodate the length of the engine. If space permits, the QR length should be kept slightly longer than the lengths of two locomotives.
Working Principle of Triangle
The working of triangle is very simple and it is very easy to understand. If an engine is standing at S facing towards P and the engine moves in the direction of arrows(i.e along SQ track) as shown[Now, in simple way we can say a train moves from S to Q, then Q to R, then back R to Q, and then Q to P], it will be facing S when it reaches point P.
You can Understand by watching this Video
Importance Features of Triangle
i. It consists of two simple turnouts (i.e., at S and P) and one symmetrical split at Q.
ii. This type of track junction has three acute angle crossing as shown in the figure.
iii. This is mainly used for turning the faces of engines where the provision of the turntable is costly.