Railway track

Railway track (CwthE and UIC terminology) or railroad track (NAmE), also known as permanent way (per way) (CwthE) or "P way" (BrE and Indian English), is the structure on a railway or railroad consisting of the rails, fasteners, sleepers (railroad ties in American English) and ballast (or slab track), plus the underlying subgrade. It enables trains to move by providing a dependable, low-friction surface on which steel wheels can roll. Early tracks were constructed with wooden or cast-iron rails, and wooden or stone sleepers. Since the 1870s, rails have almost universally been made from steel.