How A Track Switch Works
The railroad switch is a marvel of engineering. The ability to smoothly divert a fast moving train from one track to another is really what makes railroading possible.
How you get from here to there
A switch creates two tracks: The main track and a side track turning either left or right. The photo above is a right-hand turnout.
The heart of a switch is a pair of tapered rails called points which lie between the running rails and are slightly narrower in gauge. The points are hinged at one end and are controlled at the sharp end by a connection rod from the switch stand next to the track. When the switch stand lever is thrown, the points move from one running rail to the other. As the points move from side to side, a pair of sign plates (called targets) on the switch stand turn 90 degrees. Traditionally, the targets have consisted of one green plate and one red plate. The targets can be seen from either end of the switch, but only one color is visible at a time. The color of the target indicates the position of the switch: Green for the main track and red for the side track.
At the other end of the switch, where the main track separates from the side track, a “V”-shaped steel casting creates a gap on either side of the “V” to permit wheels to pass through on either track. This section of the switch is called “frog” because it resembles frog legs.
When the switch points are moved, a 5-inch gap is created alongside one of the running rails. This gap permits the wheel of the car or locomotive to go straight through the switch on the main track or into the turnout.
