metals

In rail operations, metals means the physical steel rails, sleepers, ballast, and the ground they sit on, that a railway company owns or operates. It is the infrastructure itself, distinct from the trains that run on it or the business that owns them. When a rail engineer says "we need to relay ten miles of metals," they mean replacing the actual track structure.

The term originates from the fundamental material: the rails themselves are metal (steel or historically iron), and this word came to encompass the entire fixed installation. A company might own its own metals or lease running rights over another operator's metals. The distinction matters in rail accounting and operations because metals represent massive capital assets that require continuous maintenance.

Metals include not just the running rails but the check rails, guard rails where fitted, all fasteners, and the formation beneath. The condition of metals is measured by ultrasonic testing, visual inspection for corrugation and wear, and measurement of rail head profile. Worn or damaged metals can restrict train speed and increase operating costs; a rail may become uneconomical to repair at a certain tonnage throughput.

Maintenance of metals falls into distinct categories. Routine work includes tamping (adjusting ballast), cleaning ditches, and lubrication. Heavier work involves rail grinding to restore profile, or spot renewal of sections. Complete relaying, where entire rail lengths are replaced, happens every 20 to 40 years depending on traffic type and tonnage. Heavy freight routes wear metals faster than passenger lines at equivalent speed.

The gauge of metals, the distance between the two rails, is standardized within a network but varies between regions. Standard gauge in most of Europe and North America is 1,435 mm (4 feet 8.5 inches). Narrow-gauge metals exist on heritage railways, industrial sidings, and mountain railways. A company's metals form part of its balance sheet as a depreciating asset.