What is a Railway Switch (Turnout)? How Trains Change Tracks

November 26, 2025 7:12 am

A Railway Switch, also known as a Turnout (in the US) or Points (in the UK), is a mechanical installation enabling railway trains to be guided from one track to another. Unlike cars, trains cannot steer; they follow the rails. Therefore, the track itself must move to change the train’s direction.
Switches are essential for railway flexibility, allowing trains to move between lines, enter sidings, or cross over to parallel tracks.

How Does a Switch Work?

The mechanism relies on the wheel flange (the lip on the inside of the train wheel).
Switch Rails (Points): These are movable rails. When set to one position, they guide the wheel flange straight ahead. When moved to the other position, they guide the flange onto the diverging track.
Stock Rails: The fixed outer rails against which the switch rails rest.
The Frog (Crossing): The intersection point where two rails cross. It allows the wheel flange to pass through the rail that crosses its path.
Guard Rails (Check Rails): Short rails placed opposite the frog to ensure the wheels follow the correct path and do not derail at the gap.

Types of Railway Switches

Type	Description	Typical Usage
Simple Turnout	A single track dividing into two.	Most common switch everywhere.
Diamond Crossing	Two tracks crossing each other without connecting.	Intersections (Flat junctions).
Scissor Crossover	Two parallel tracks connected by two crossovers in an X shape.	Stations and busy terminals.
Slip Switch	A diamond crossing that also allows trains to change tracks.	Space-constrained areas (depots).

High-Speed Switches

Standard switches have speed limits (often 40 km/h or less) for the diverging path. However, High-Speed Switches use “Swing Nose Frogs” (Movable Point Frogs) to close the gap at the crossing, allowing trains to change tracks at speeds of up to 160 km/h or pass straight through at 300+ km/h without vibration.