Russian Railways (RZhD) is the government-owned railway company of Russia, and is one of the largest in the world, in terms of employees (1.2 million), traffic, rolling stock and length of track.
Shcherbinka Experimental Loop Proving and Testing Centre
The Neoloy™ version of PRS-Neoweb was tested at the Russian Railway Research Institute’s (VNII ZhT) Experimental Test Loop near Moscow. PRS-Neoweb was installed over soft clay subgrade underneath a 40 cm ballast layer. Diagnostic tools on test carriages and sensors in the three substructure layers enable the evaluation of the amount of deformation vs. traffic and loading.
Challenge – Reinforce Soft Permafrost Soils
PRS-Neoweb also was deployed in the Arkhangelsk Province of the RZD (Russian Railways) to strengthen the track formation layers in “ailing” sections. Traversing through permafrost bogs where the rail embankment and structural support layers are subject to steady deformation, these sections need frequent rehabilitation. PRS-Neoweb strengthens the track substructure by forming a semi-rigid beam that provides uniform rigid support of the upper structural layers. It also reduces settlement and accumulated degradation caused by the weak subgrade.
PRS-Neoweb Solution – Increases Speeds & Loads
After removing the old track and ballast, 15 cm PRS-Neoweb was installed in the sub-ballast layer. Infill consisted of a sand-gravel mixture, with 6-10 cm compacted overfill. The infill was dropped from a rail chute at a height of several meters without damage to the stiff cell walls. A new layer of 60 cm ballast, along with new sleepers and rails were laid down on the top layers.
The Head Supervisor of the Geotechnical Evaluation Center of RZD, Vitaly Leonyuk, stated that: “the PRS-Neoweb reinforcement subbase layer prevents deformation in the embankment and structural layers as a result of the dynamic loading” and “it enables trains to pass over these problematic sections at higher speeds and at heavier axle loads.” RZD plans to install 68 thousand square meters of PRS-Neoweb geocells in the rehabilitation of 13.6 km of problematic track in this Northern region.
The so-called “ailing” sections make up some 3% of the entire RZD rail network (85,500 km), and implementation of Neoweb in these sections alone will eliminate safety risks and enable trains to travel at normal speed limits through these areas. PRS-Neoweb offers the following benefits:
- Engineering: Increases bearing capacity, reduces structural layer thickness while using inferior quality infill; prevents aggregate attrition; outperforms any geogrid.
- Material: Long-term resistance to creep, oxidation, temperature extremes, UV light – extends lifespan of substructure; outperforms any HDPE geocell.
- Operational: Fast installation, good drainage, reduces track vibrations and deflection, increases performance (40% heavier loads and 30% faster speeds)
- Economic: Lower initial construction costs, very long-term ballast and track durability results in low total cost of ownership, improved service, safety and reliability, frees maintenance budgets for new track construction.