RIDIN' THE RAILS WITH THE DEFECT HUNTERS

Railroad track is often seen as an unchanging part of the landscape, but in reality, track is dynamic. A fleet of specially equipped cars called Track Structure Assessment Vehicles or Track Geometry Cars carefully monitors the track, because a variation of just one inch (2.54 cm) in a rail's location or geometrical position can derail a freight train weighing thousands of tons. Track is checked to gauge, parallel alignment, curvature, cross-level, and vertical profile.