A track bed or trackbed is the term used to describe the groundwork onto which a railway track

Rail tracks

The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...

 is laid. Trackbeds of disused railways are sometimes used for recreational paths

Rail trail

A rail trail is the conversion of a disused railway easement into a multi-use path, typically for walking, cycling and sometimes horse riding. The characteristics of former tracks—flat, long, frequently running through historical areas—are appealing for various development. The term sometimes also...

 or new light rail

Light rail

Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

 links.

According to Network Rail

Network Rail

Network Rail is the government-created owner and operator of most of the rail infrastructure in Great Britain .; it is not responsible for railway infrastructure in Northern Ireland...

, the "trackbed" is the layers of ballast

Track ballast

Track ballast forms the trackbed upon which railway sleepers or railroad ties are laid. It is packed between, below, and around the ties. It is used to facilitate drainage of water, to distribute the load from the railroad ties, and also to keep down vegetation that might interfere with the track...

 and sub-ballast above a prepared subgrade

Subgrade

In transport engineering, subgrade is the native material underneath a constructed road, pavement or railway track. It is also called formation level.The term can also refer to imported material that has been used to build an embankment....

/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, 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 of passenger services.