A siding, in rail terminology, is a low-speed track section distinct from a running line or through route such as a main line, branch line, or spur. It may connect to through track or to other sidings at either end. Sidings often have lighter rails, meant for lower speed or less heavy traffic, and few, if any, signals. Sidings connected at both ends to a running line are commonly known as loops; those not so connected may be referred to as single-ended or dead-end sidings, or stubs.
Railway sidings (left) beside the main running-lines (right) at Kingswear in Devon, England
On single-track lines, trains use passing sidings to pass one another. One Canadian Pacific Railway train waits on a siding while a second train passes.
Rail cars parked on sidings in Switzerland
Example of multiple team tracks
Glossary of rail transport terms
Rail transport terms are a form of technical terminology applied to railways. Although many terms are uniform across different nations and companies, they are by no means universal, with differences often originating from parallel development of rail transport systems in different parts of the world, and in the national origins of the engineers and managers who built the inaugural rail infrastructure. An example is the term railroad, used in North America, and railway, generally used in English-speaking countries outside North America and by the International Union of Railways. In English-speaking countries outside the United Kingdom, a mixture of US and UK terms may exist.
A Swiss axle box
The backhead of UP 4017, a locomotive at the National Railroad Museum in Green Bay, Wisconsin
Boom barriers at a railway crossing in France
A caboose on display at the National New York Central Railroad Museum