This document specifies the laboratory method for measuring the airborne sound insulation performance of railway noise barriers in reverberant conditions. It covers the assessment of the intrinsic performance of noise barriers and related devices acting on airborne sound propagation that can reasonably be assembled inside the testing facility described in EN ISO 10140-2 and EN ISO 10140-4. This method is not intended for the determination of the intrinsic characteristics of airborne sound insulation of noise barriers to be installed on railway in non-reverberant conditions. All noise reducing devices different from noise barriers and related devices acting on airborne sound propagation, e.g. devices for attenuation of ground borne vibration and on board devices, are out of the scope of this document.