USM®G #
The G-series of the USM® track mats have on the surface that faces either the ballast or the concrete slab a fabric reinforced chloroprene layer which is abrasion, oil, ozone and weather resistant.
Read more:
http://www.calenberg-ingenieure.com/pr-railway-construction-sub-ballast-mats-trackbed-mats-lmss.htm