GPR

The overall aim of this project was to relate ground penetrating radar (GPR) to a ballast fouling index (FI). Laboratory research aimed at characterising the electromagnetic properties has enabled researchers worldwide to determine ballast thickness using impulse ground penetrating radar (GPR) - based upon derived values of the relative electrical permittivity or dielectric constant.

The number of rail passenger and miles travelled has dramatically increased over the past 15 years. Network Rail is the operator of the UK infrastructure network and is responsible for managing over 32,000 km of track. In order to maintain the required standards of comfort and safety Network Rail spends over one billion pounds (sterling) each year on maintenance alone. Traditional methods of determining when maintenance was required were time consuming and expensive, which lead to the use of non-destructive testing (NDT), particularly GPR, as a method of monitoring track conditions.