Aurora Xi is an X-ray backscatter system that detects density changes in wood crossties at speeds up to 25 miles per hour. This system is mounted on a hi-Rail inspection vehicle and is used to inspect ties that are installed on active railways nationwide. The X-ray data is aligned with a 3D laser profile of the surface. Together, they promote maximum data mining between surface and sub-surface anomalies. Data analysis is performed by automated image processing algorithms and exception reports allow customers to prioritize the allocation of tie resources based on the most comprehensive data available. Since 2005 Georgetown Rail Equipment Co. has operated an automated tie inspection system, Aurora, which annually inspects approximately 45,000 miles of crossties in North America. This system employs a 3D laser-profiling technology, which accurately identifies tie surface failure modes such as plate cutting, checking, splitting, surface roughness, warpage and other factors.