Sidings are relatively short stretches of track used to 'set-aside' trains and parts of trains from the main running lines. This is useful:
- to allow other trains to pass,
- to facilitate the loading or unloading of freight or passengers, and / or
- for the servicing / storage of locomotive and rolling stock.
For the purposes of the SCRCA Project, lie-by sidings, spurs, loops, headshunts, railway tracks in goods-yards and railway tracks in locomotive servicing areas are all classified as 'sidings'. Also, the term is used to indicate a single siding or a group of associated sidings: in other words, a 'siding' is any railway track that does NOT form one of the two main running-lines.