Track substructure characterization using 500 MHz & 2 GHz ground penetrating radar: Results from track in Colorado, Wyoming, & Alaska, USA

In June, July and August, 2007, a configuration of ground penetrating radar (GPR) antennas mounted on a hi-rail vehicle was used to assess the ballast condition and characterize the subballast and subgrade along over 252 mi (406 km) of track in Colorado, Wyoming and Alaska, USA. The GPR setup utilized...