RADAR reflective strips are laminated into the Terram PW5 geotextile, enabling ground-penetrating radar to be used to confirm that the correct depth of ballast is present after a track renewal project.

The non-woven material was developed by Terram in collaboration with Network Rail, and after tests in the UK it is currently being trialled on TGV Est in France. The 50 mm wide conductive strips have clearly-defined edges visible to the radar, enabling computer analysis of the return signals to be used to measure the position of the geotextile and the depth of ballast above it.

Three radar reflective strips are provided, allowing the differences in height of the polypropylene-polyethylene geotextile to be identified.

H Research on 400m of Network Rail’s West Coast Main Line and at Nottingham University’s Railway Test Facility demonstrated a minimum threefold increase in the maintenance life of ballast over a poor formation when reinforced with an appropriate geogrid. The Royal Society funded research team included geogrid maker Tensar International, Scott Wilson and Carillion.

Terram, UK,

Tensar International, UK