Editing Track ballast (section)

{{Short description|Trackbed upon which railway ties are laid}}
{{other uses|Ballast (disambiguation)}}
{{Use dmy dates|date=January 2021}}
[[File:Rails.and.ballast.bb.jpg|thumb|right|Good quality track ballast is made of [[crushed stone]]. The sharp edges help the particles interlock with each other.]]
[[File:Close-up of railway track.jpg|thumb|Track ballast supports railway sleepers, which carry railway track.]]

'''Track ballast''' is the material which forms the [[trackbed]] upon which [[railroad tie]]s (UK: sleepers) are laid. It is packed between, below, and around the ties.{{sfnp|Solomon|2001|p=18}}  It is used to bear the compression load of the railroad ties, rails, and [[rolling stock]]; to facilitate [[drainage]]; and keep down [[vegetation]] that can compromise the integrity of the combined track structure.{{sfnp|Solomon|2001|p=18}} Ballast also physically holds the track in place as the trains roll over it. Not all types of railway tracks use ballast.<ref> [https://www.railjournal.com/in_depth/tubular-track-tames-the-desert Tubular Modular Track]</ref>

A variety of materials have been used as track ballast, including [[crushed stone]], washed [[gravel]], bank run (unwashed) gravel, torpedo gravel (a mixture of coarse sand and small gravel), [[slag]], [[Chat (mining)|chats]], [[Ember|coal cinders]], [[sand]],<ref>{{Cite web|last=Kellogg|first=H. W.|title=Selection and Maintenance of Ballast|year=1946|url=https://www.arema.org/files/roadmasters/1946/1946-Selection-and-Maintenance-of-Ballast.pdf|website=American Railway Engineering and Maintenance-of-Way Association|access-date=27 March 2021}}</ref> and burnt [[clay]].<ref>{{Cite book|last1=Beyer|first1=S. W.|last2=Williams|first2=I. A.|title=The Geology of Clays|year=1904|url=http://ir.uiowa.edu/cgi/viewcontent.cgi?article=1078&context=igsar|archive-url=https://web.archive.org/web/20100813010824/http://ir.uiowa.edu/cgi/viewcontent.cgi?article=1078&context=igsar|url-status=dead|archive-date=13 August 2010|publisher= |location= |pages=534–537}}</ref> The term "[[ballast]]" comes from a nautical term for the stones used to stabilize a ship.{{sfnp|Solomon|2001|p=18}}