Products: PW1 - trackbed separator, PW2 - trackbed robust separator, PW4-LA - trackbed separator/reinforcement

Terram Geosynthetics provide solutions for permanent way applications where loss of rail track alignment caused by sub-grade erosion leads to costly maintenance and the complication caused by having to plan and temporarily close the track for its renewal.

The traditional solution has been to use a sub-ballast and/or a graded-sand layer to prevent the upward movement of fine sub-grade particles. Some 25 years ago, the use of a simple geotextile was adopted to maintain separation between the adjacent sand/ballast layers – Terram PW1 geotextile.

Since then further geosynthetics have been developed for permanent way applications and employed to deal with related issues:

• Terram PW2 geocomposite- a robust separator/filter incorporating a stiff net between two textile filter layers
• Terram PW4-LA is a composite formed from Terram 4000 and Tensar SS40LA geogrid. Tensar SS40 improves track life and performance by stiffening ballast laid over weak ground. The advantage of Terram PW4-LA is the speed at which a geotextile filter and grid reinforcement can be laid in a single pass with the beneficial effect on construction costs..

The choice of Terram PW grade will depend on the sub-grade type & its strength.