{{Short description|Base portion of a railway-supporting structure}} {{mdy|date=February 2024}} thumb|Section through railway track and foundation showing the ballast and formation layers [[File:Railroad tracks northbound, Matfield MA.jpg|thumb|A view of track bed in Massachusetts]]
The '''track bed''' or '''trackbed''' (or '''railroad bed''') is the groundwork onto which a railway track is laid. Trackbeds of disused railways are sometimes used for recreational paths or new light rail links.
==Background== According to Network Rail, the trackbed is the layers of ballast and sub-ballast above a prepared subgrade/formation (see diagram). It is designed primarily to reduce the stress on the subgrade.
Other definitions include the surface of the ballast on which the track is laid,<ref name="Ellis">{{Ellis' Railway Encyclopaedia}}, p. 386.</ref> the area left after a track has been dismantled and the ballast removed<ref name="Ellis"/> or the track formation beneath the ballast and above the natural ground.<ref>{{Railway Dictionary|page=297}}</ref>
The trackbed can significantly influence the performance of the track, especially ride quality of passenger services.
== See also == * Embankment (transportation) * Green track * Roadbed * Subgrade
==References== {{Wiktionary|trackbed|track bed}} {{Reflist}}
{{Geotechnical engineering}} {{Authority control}}
Category:Fills (earthworks) Category:Permanent way