System

Variable

Geometry system

Left/right elevation, gauge, left/right track alignment, level, warp, change rate of curvature, track quality indicators, change rate of track quality variables

Rail system

Spalling and chipping, flow of rail head or working edge, rail joint malocclusion on the top or inner side, rail vertical wear, rail side wear, scaling, rail head transverse damage, abnormal light band, screw hole transverse crack

Connecting part system

Fastener missing, fastener skewed, fastener buried; rubber gasket skewed

Sleeper system

Sleeper deflection, sleeper chipping, sleeper crack, number of sleepers, sleeper spacing

Subgrade ballast system

Thickness, ballast bed smudgy, ballast bed smudging

Operating system

Total mass of passing trains