Railroad inspection is the practice of examining tracks for flaws. The railroad industry inspect thousands of miles of rails each year to find cracks that could lead to a derailment. NDT also tests locomotive and rolling stock axles for fatigue cracks.

The major components subjected to various NDT methods are :

1. Rails
2. Wheels
3. Axels
4. Bearings
5. Welded rail joints
6. Brides