![Section through railway track and foundation](https://upload.wikimedia.org/wikipedia/commons/a/a5/Section_through_railway_track_and_foundation.png)
The track bed or trackbed is the groundwork onto which a
railway track
A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, ...
is laid. Trackbeds of disused railways are sometimes used for
recreational paths or new
light rail links.
According to
Network Rail
Network Rail Limited is the owner (via its subsidiary Network Rail Infrastructure Limited, which was known as Railtrack plc before 2002) and infrastructure manager of most of the railway network in Great Britain. Network Rail is an "arm's leng ...
, the trackbed is the layers of
ballast
Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, ...
and
sub-ballast
Track ballast forms the trackbed upon which railroad ties (sleepers) are laid. It is packed between, below, and around the ties. It is used to bear the load from the railroad ties, to facilitate drainage of water, and also to keep down vegetat ...
above a prepared
subgrade
In transport engineering, subgrade is the native material underneath a constructed road,http://www.highwaysmaintenance.com/drainage.htm The Idiots' Guide to Highways Maintenance ''highwaysmaintenence.com'' pavement or railway track (US: railroad ...
/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,
[, p. 386.] the area left after a track has been dismantled and the ballast removed
or the track formation beneath the ballast and above the natural ground.
The trackbed can significantly influence the performance of the track, especially
ride quality
Ride quality refers to a vehicle's effectiveness in insulating the occupants from undulations in the road surface (e.g., bumps or corrugations).
A vehicle with good ride quality provides a comfort for the driver and passengers.
Importance
Good r ...
of passenger services.
See also
*
Embankment (transportation)
A road, railway line, or canal is normally raised onto an embankment made of compacted soil (typically clay or rock-based) to avoid a change in level required by the terrain, the alternatives being either to have an unacceptable change in lev ...
*
Roadbed
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
*
Subgrade
In transport engineering, subgrade is the native material underneath a constructed road,http://www.highwaysmaintenance.com/drainage.htm The Idiots' Guide to Highways Maintenance ''highwaysmaintenence.com'' pavement or railway track (US: railroad ...
References
{{Geotechnical engineering
Permanent way
Fills (earthworks)