Rail Wear Calculator

The calculator steps the head-wear condemnation limit up with rail weight, following the published limits in Chapter 4 (Rail) of AREMA's Manual for Railway Engineering — 0.625 in for 132 lb/yd and heavier, 0.5 in for 115 to 131 lb/yd, and 0.375 in below that — because a heavier rail section simply has more head material to wear through before the rail's structural profile is compromised. A heavier rail therefore tolerates more absolute wear even at the same wear rate, which independently extends its service life in MGT.

The base wear rate (set by curvature alone) is multiplied by your lubrication factor and divided by a rail-grade multiplier: effectiveWearRate = baseWearRate × lubricationFactor / gradeMultiplier. Lubrication ranges from 1.0 (none) down to 0.3 (excellent gauge-face lubrication) and directly scales wear down, while rail grade divides it further — head-hardened rail gets a 1.5x divisor and premium alloy a 2x divisor, reflecting that harder steel resists the same contact stress longer.

The calculator uses three curvature bands with different slopes: mild curves (up to 3°) add 0.5 mm per 100 MGT per degree on top of a 1.5 base, moderate curves (3-8°) add 0.8 per degree on a higher 3.0 base, and sharp curves (above 8°) add 0.5 per degree on a 7.0 base. This reflects that flange and gauge-face contact stress escalates faster than curvature itself as curves tighten, so a small increase in degree of curve on a sharp curve represents real additional wear even though the per-degree increment looks smaller than the moderate band's.

On curved track, the interval is max(10, 30 − degreeOfCurve × 2) MGT, so sharper curves get ground more often — as low as 10 MGT for very sharp curves — because grinding removes surface defects before they compound into deeper wear where contact stress is highest. Tangent track defaults to a flat 50 MGT interval since it isn't subject to the same flange and gauge-face stress.