Experimental variability of track to ground conductance measurements

To fulfil IEC 62128-2 (EN 50122-2) standard stray current requirements, the new or revamped DC electrified transportation systems shall achieve very good levels of track to ground insulation. This insulation shall be witnessed, usually in construction phases, by means of accurate measurement. Some measurement techniques are suggested by IEC 62128-2 standard but literature leaks about considerations about their measurement uncertainty. The paper purpose is to fill this gap and analyse the variability of track to ground conductance measurements.