Standards Development

In 1992, ARRT began developing standards and policies for track and its components for the railways. Today, ARRT is the only organization in North America that sets Rail Wear Limits.

Currently, railways compute track Superelevation based on the balanced speed of one wheel and then reduce the computed value by an arbitrary number called “unbalanced superelevation”. This does not consider multiple wheels in the vehicle, the degree of curvature, grade and rolling resistances and, the associated drawbar forces, thermal effects and power distribution in the train. Uphill, the drawbar forces pull the track inwards. Downhill on the same curve, the cars try to buckle the track outwards requiring a different superelevation. This discrepancy in elevation requirement for the same curve gets worse with increase in the degree of curvature and causes constant movement of the curves, track buckling at exits of curves and track component damage. ARRT’s experiences show that proper rail management and optimization of track asset life cannot be achieved without superelevation policies that respect the terrain and what the trains want.

Other policies developed by ARRT include criteria for allowing a train to slowly and safely traverse a rail break, prediction of rail fracture during a cold snap, residual stress specifications currently used in AREMA, etc.