Railways

The Challenge – Reducing Railway Maintenance

The 457-mile mainline Northeast Corridor, from Washington DC to Boston is one of the highest volume rail corridors in the world, carrying 2,200 commuter and freight trains daily. A problematic section of track in the state of Maryland passes through soft clay subgrade with poor drainage that fouls the ballast. High speed railways are very sensitive for track geometry degradation. This necessitates frequent, expensive tamping every 3-4 months and results in speed limitations and a degradation of service.

Innovative Technology for High Speed Railways

As part of Federal Railway Administration (FRA) program to promote innovative technologies that will advance high speed railways, Amtrak (US National Railroad Corporation), Harsco Rail Consulting Group and Columbia University – have evaluated several geosynthetics solutions. Click Here to read Prof. Alan Zarembski testimonial.

Neoloy Geocells provide the best performance for Railway Track Reinforcement

After evaluating several soil stabilization solutions, including moisture barriers, geogrids and HDPE geocells –  Neoloy Geocells showed the best results for track reinforcement:

• Track Maintenance Cycles were reduced by a factor of 7.
• Track Quality Index (TQI) Score was improved by a factor of 2.
• Return of Investment (ROI) is expected to be within a year.

Neoloy Geocells – the Best Solution for Railway Track Reinforcement

Neoloy Geocells are made of a unique Novel Polymeric Alloy (NPA) providing the following properties:

• High tensile strength – high ground reinforcement factor
• Low permanent deformation (creep) under loading – sustain long-term performance.
• High Elastic Stiffness– sustaining high stress without deformation.

These properties provide the best performance for railway track reinforcement –  track geometry is preserved for long-term, at the lower costs.

The Neoloy Geocell system is based on a hybrid structure of geocell on geogrid working platform. Neoloy Geocells Category D (Heavy Duty) were installed at the ballast/sub-ballast interface. The geogrid was installed on the subgrade layer as a working platform.

Fast Implementation, Quick Investment Return

Knowledge transfer for the Amtrak installation team went smoothly. The entire operation took place during a long weekend when the track was removed from service. Standard Amtrak quality ballast and sub-ballast were used. The impact of Neoloy was noticeable immediately – the trucks hauling infill caused severe rutting to the wet mud subgrade as they approached the installation area, but easily traversed the areas in which Neoloy Geocells were already installed with no rutting whatsoever.

Click here to read more about this project

Prof. Allan Zarembski, Director of Railroad Engineering and Safety Program, University of Delaware testimonial

Churchill is an extremely remote town in Northern Manitoba with a population of ~1000. Accessible only by boat, air or rail, it is a popular destination for tourists to see polar bears, whales and the aurora borealis. However, after a flood washed out 30 sections of the railway (total of 2 km) in early 2017, the town was cutoff by land for nearly 18 months. The absence of the railway and reliable supplies of necessities affected the sense of wellbeing of the residents, as well as some 40 First Nations communities in the area. A solution to remediate the rail line was essential.

Churchill is on an ecotone between three regions: boreal forest, Arctic Tundra, and Hudson Bay. The rail line offered little shelter from the elements, making the weather conditions more extreme. The ground was soft with a CBR of 1%. Paradox prepared their team properly and pre- planned the use of Neoloy Tough Cells technology to fix the rail line and make it resistant to the challenging conditions.

Designing sustainable infrastructure with limited engineering data is always a challenge, especially when it comes to an area where damage to the environment should be minimal. Rehabilitation of the century-old Gillam to Churchill railway line crossing had similar challenges as it passed through the vast permafrost region of Northern Manitoba.

 “The rail line was damaged by flood and possible damage to the underlying permafrost. Compounded with the harsh winter weather, shorter construction season, and a linear construction sequence, we needed a solution that could address all these issues and complete the work within reasonable time and budget.” Dr. S. Pokharel, Stratum Logics, Geotechnical and EPCM Services

NEOLOY® TOUGH CELLS SOLUTION

A typical railway must be able to withstand the most challenging demands— weather combined with the weight, speed and frequency of loads travelling its rails. Add in permafrost and muskeg to increase the challenge exponentially. That’s where the Neoloy® Tough Cells® technology come in. Tough Cells —a cellular confinement and soil stabilization product made of a Novel Polymeric Alloy (NPA) by PRS—is uniquely suited to constructing railway in permafrost and muskeg areas, where an unstable substrate can lead to lateral spreading of ballast and differential settlement of the railbed.

Tough Cells’ honeycomb structure provides lateral restraint of ballast—and leads to the entire track settling together. That extends the life of the railbed and lowers cost of maintenance. Proper application of Tough Cells in permafrost conditions can also prevent melting, which further preserves railbed integrity. Compared to conventional ground stabilization methods, Tough Cells require less construction time, are more cost-effective, and have a significantly smaller carbon footprint.

Due to the remote location, transporting necessary materials and Paradox workers was an obstacle. A 50-mile trip with a heavy load, the train could only travel 7 mph. The rail line speed was 15-20 km/hr making the journey slow. In turn, this required the Paradox team to pre-plan accordingly to ensure that there were enough materials and scheduled labor for the team. Additionally, Paradox recycled onsite materials to ensure that supply levels were kept consistent.

Advantages

• Reduced settlement of ballast materials and fouling by subgrade attrition.

Benefits

• Stable track, improved service, reduced maintenance.

Results

• Paradox completed the project in under 60 days—ahead of schedule, on quality, and on budget and met the highest quality standards. With the rail up and running, and its ability to operate safely and efficiently no matter the conditions, Churchill and surrounding communities now have consistent and reliable access to necessities.

Video about using Neoloy® Tough Cell solution in Hudson Bay Rail Line repair project

Read more about this project

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 the track.

In the Arkhangelsk Province of the RZD (Russian Railways) the rail embankment and structural support layers, traversing through permafrost bogs, are subject to steady deformation. Neoloy Geocells were deployed to strengthen the track formation layers in “ailing” sections by forming a semi-rigid beam that provides uniform rigid support of the upper structural layers and reduces settlement and accumulated degradation caused by the weak subgrade.

Neoloy Geocell Solution – Increases Speeds & Loads

After removing the old track and ballast, 15 cm of Neoloy 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 Neoloy 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 Neoloy Geocells in the rehabilitation of 13.6 km of problematic track in this Northern region.

Benefits

• Operational: 40% heavier loads and 30% faster speeds
• Engineering: Increased bearing capacity, reduced structural layer thickness, prevented aggregate attrition
• Material: Long-term resistance to creep, oxidation, temperature extremes, UV light
• Economic: Lower initial construction costs, long-term ballast and track durability, improved safety and reliability, frees maintenance budgets for new track construction.

As part of its program to upgrade and rehabilitate track and construct new lines, Israel Railways adopted the Neoloy Geocell technology as its preferred method for track rehabilitation over problematic subgrade. This includes improving load support over soft sandy soils and restraining volumetric change in fat clay soils.

A new 16 km Southern rail line from Tel Aviv passes through a number of suburbs, originally built over sand dunes. Whereas, the route passes through weak subgrade, the rail authority and geotechnical consultants decided to utilize Neoloy Geocells to reinforce the substructure along the entire line. In addition to improving the load bearing capacity, Neoloy was selected for its overall performance, durability and long-term cost savings in track operations and maintenance.

Conventional Approach

Conventional subgrade improvement methods include thick layers of expensive ballast and subballast and/or the use of geogrids for reinforcement. However geogrids require high quality subballast aggregate, while their zone of confinement is limited. Reduction of the subballast layer is minimal, and these solutions require frequent maintenance.

Neoloy Geocell Solution

The Tel-Aviv to Ashdod rail line utilized Neoloy Geocells of 20 cm wall height for subgrade reinforcement of the subballast layer. A total of 200,000 m2 is being installed in 12m wide sections along the 16 km rail route. Medium grade, fine granular infill material was sufficient for the heavy load support needed for the railway substructures. Whereas, the Neoloy vertical zone of influence provides 30-50% more confinement and reinforcement than other solutions, attrition of the aggregate and ballast infill is reduced significantly. The result is that track geometry is sustained for longer periods of time thereby reducing the number of expensive maintenance cycles.

Benefits

• Reduction of required excavation depth
• Reduction in periodic maintenance and rehabilitation
• Cost-effective rapid installation
• Facilitates faster speeds and heavier loads without track degradation
• Field testing showed that track maintenance cycles with Neoloy Geocells can be extended by 3x