Rail ballast: conclusions from a historical perspective

Although it is now universally accepted that good-quality hard angular stone of nominal size 40–50 mm is the best material for ballast, historically track has been for longer on non-stone ballast than on stone ballast. Even the stone ballast specified up until the 1980s was of a smaller average size than present ballast. Research into the two-layered ballast system and a study of development of ballast specification from the early 1900s suggests that current ballast specifications should be changed to ballast of smaller size. This would: cause substantial reduction in maintenance requirements for ballasted railway track; reduce track noise levels; provide better ride quality; and increase ballast life.