A short stretch of railroad track used to store rolling stock or enable trains on the same line to pass WordNet 3.0 & Open English WordNet

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. Wikipedia

A track section Wikipedia Disambiguation

Type of railway track Wikidata

Any auxiliary railroad track, as differentiated from a siding, that runs adjacent to the main track. Wiktionary

A second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for loading or unloading freight, storing trains or other rail vehicles; or to allow two trains on a same track to meet (opposite directions) or pass (same direction) (the latter sense is probably an American definition). Wiktionary

Side track. Wiktionary (translation)

A place where moveable rails allow a train to switch tracks; a set of points. Wiktionary