The GPR technology has been introduced to the railroad engineers as one of the easy tools for quick and non-invasive railroad inspection. Since these surveys tend to stretch for a number of kilometers the amount of data can be overwhelming. However, with some clever preparations and proper tools for post processing the data one can create swift and easy to understand reports. These reports will be highly precise and at the same time the results can be combined with many other methods (borehole, auger hole, dynamic stress tests). The biggest benefit of GPR survey is that the equipment can be mounted on almost any standard train wagon/locomotive and then connected to any train composition. This allows you to collect the data without closing the section of the railroad for regular traffic.
Higher frequency antennas are used to determine ballast layer fouling. Lower frequency antennas are used to locate anomalies in the ballast and sub-grade layers (water eroded places, water pockets, voids etc..). Usually the survey is providing the information about the left /right shoulder and the center line of the railroad. By combining lower and higher frequency antennas the survey's scope can be set for each of the lines.
Railroad survey application