Where to measure the gage:
Gage is measured between the heads of the rails at right angles to the rails in a plane five-eighths of an inch below the top of the rail head.
The following factors might affect the gage:
- Evidence of recent rapid deterioration of gage with probable continued deterioration;
- Evidence of recent significant damage to rail fasteners to the extent that gage widening is probable;
- Evidence of recent maintenance work improperly performed resulting in lack of sufficient fasteners to prevent gage widening under expected traffic;
- Traffic conditions, including speed, tonnage, and type of equipment; and Conditions of curvature and grades.