Research into Track Bed ReinforcementApplications

Research into Track Applications

UK Trials, Installations and Research

Fullscale trial using 40 tonne rolling rig

Tensar geogrids can help extend maintenance intervals by minimising settlement. Full-scale, independent research by British Rail clearly showed that over soft subgrade soils:

• The rate of settlement approaches that of track on a firm foundation when using Tensar geogrids in ballast
• Tensar geogrid has a stiffening effect and will reduce the elastic deflections
• Reinforced track will experience more rapid settlement and will require additional maintenance
• The use of grids with high profile ribs can limit the lateral creep of ballast particles, reducing settlement and, therefore, the rate of deterioration of the vertical track geometry

Contemporary research in the UK

Loading at the Nottingham University RTF

The University of Nottingham have recently led a major UK reserach and development project which quantified the permanent settlement of track and investigated the use of Tensar geogrids to control the settlement of track ballast and increase periods between maintenance.

The Nottingham Rail Test Facility allows a full scale section of rail track, three sleepers in length to be tested.

Three seperate installations were tested to a million cycles and settlement was measured. The results showed that the use of Tensar large aperture geogrid coudl increase the intervals between maintenance interventions by a factor of at least 2.5

There is a more detailed analysis of the tests provided in the Tensar Railways Brochure which can be downloaded from the download section of this website.

UK East Coast Main Line

Full-scale trials have also been carried out on the UK East Coast Main Line where it passes through low-lying peaty fens. This length of track had required considerable maintenance and operation at reduced speeds.

In 1996, UK rail operator, Railtrack reported that: "Over the 5-6 years since installation, the general condition of the track in this area had shown a much greater stability throughout the annual cycle of climate changes than it did prior to the work being carried out." Tensar SS40 has Railtrack product acceptance for the structural reinforcement of railway ballast.

Railway Trials - Germany

Installation of Tensar SSG geocomposite

The German Rail Authorities have also carried out full-scale trials during track widening over soft soils. Plate-bearing tests revealed that the bearing capacity of both 400mm and 600mm thick ballast layers reinforced with a Tensar SS geogrid was increased by a factor of 2 compared with the same unreinforced thickness.

A selection of relevant brochures that may be downloaded are listed on the top right of this page. Alternatively click here for a full list of relevant brochures and case studies

If you would like free impartial advice on Tensar solutions for your project, visit our Solid Advice page.