Ballastless track system solutions are the way to move forward building the new track future for a developing economy like India – a country requiring fast, safe and reliable infrastructure for higher mobility of its rapidly growing population.
Proven in decade-long experience under demanding conditions on multiple continents, one of the main advantages of ballastless track solutions in comparison with ballasted tracks is the ease of maintenance of the track itself. Beyond the maintenance of rails and fastenings resulting from wear and tear of both, the concrete track itself does not need any kind of maintenance unlike regularly tamping actions, ballast cleaning, etc. in ballasted track. And: even the wear and tear of the rail and fastening system is lower for ballastless track since state-of-the-art high elastic fastening system yields a better load distribution of 25-ton axle loads onto more subsequent rail seats of sleepers, thereby comparably decreasing the wear and tear of each fastening system. Higher accuracy in the rail alignment finally helps to reduce premature wear of the rails. Maintenance of free ballastless tracks provide a better availability and capacity of the line for higher train frequency as downtimes for maintenance actions are bare minimum.
Amongst the many advantages, there are specific aspects as well in tunnel applications, where the ballast bedding, naturally on mostly very stiff tunnel inverts, is often causing a premature deterioration of the ballast. This effect is becoming also more severe with increasing operational speeds of the trains resulting in higher dynamic impacts. Here, ballastless track solutions show a better-defined and long lasting alignment quality. More than a decade back, Deutsche Bahn (German Railway Authority) had changed their policy for ballasted tracks in tunnels by requiring either the installation of sub-ballast mats in ballasted tunnel tracks or the application of ballastless tracks where trains are operating above 160km/h. Similarly now in India, the Government has made it mandatory in its ongoing track upgrading initiative to increase axle loads from 22.5 to 25 tons to install ballastless tracks in tunnels for the same reason.
RHEDA 2000® – the most advanced slab track system solution has been developed and patented by RAIL.ONE, headquartered in Germany.
It is one of the very few Research Design Standard Organization (RDSO) approved system readily available for use. RDSO approved this system back in the year 2003. RHEDA 2000®, the latest evolutionary stage of a series of innovative systems goes back to the first trial application of a ballastless track installed in a 637m long station track in the city Rheda-Wiedenbrueck in Lower Saxonia, Germany in 1972. It was a model installation for a German Rail/Wheel Research project. Even today that track is still in service without any major maintenance for almost 50 years up to now. The first commercial applications of RHEDA track systems in considerable scale were in three tunnels of the high-speed line Hannover – Wuerzburg in the center of Germany and in one tunnel of the line Mannheim – Stuttgart in the country’s southwest in the late 1980s/early 1990s. These applications proved the assumptions of lower maintenance of slab tracks in tunnels compared to ballasted track along with savings in the overall construction height and associated savings in tunnel construction. From a general perspective, the RHEDA system works in a somewhat similar way as the Japanese Slab Tracks, since the high elastic fastening systems used with the RHEDA system provides an excellent load distribution of axle loads and reduce the load on the rails seats of the bi-block sleepers.
RHEDA 2000® system consists of continuous poured concrete slab and is equipped with continuous, longitudinal rebar for crack control purposes. In line with local requirements in India, there it is also equipped with a concrete derailment block in accordance to IRPWM (Indian Manual for Permanent Way) arranged with 250 mm clearance between the running rails. The derailment block is connected via starter bars with the RHEDA track concrete layer and also equipped with crack control rebar. The RHEDA 2000® bi-block sleeper B355.3 U60-20M-1673/76 assures the correct Indian gauge of 1673/76 mm. Once cast into concrete on site, the sleepers are monolithically embedded in the track concrete layer, assuring its long-term integrity. This track system is approved for train travelling speeds of up to 350 km/hr.
Figure 1 : Approved RHEDA 2000® cross section for Rapur Tunnel
The latest application of the RHEDA 2000® system in India was in a 6.6 km long tunnel close to Rapur, Andra Pradesh, India’s longest single track tunnel to date, in 2019 by PCM Strescon Overseas Ventures Ltd., which was inaugurated in October 2019. The material logistics (e.g. supply with fresh concrete) was a huge challenge in this long, single track tunnel and especially since other tunnel equipment works were ongoing simultaneously.
PCM Strescon Overseas Ventures Ltd is a daughter company of PCM Group of Industries, which also owns RAIL.ONE. The complete track installation was completed in a record time of less than six months.The figures below show the track in the tunnel and the Tunnel portal.
Figure 2 : RHEDA 2000® track installation in Rapur tunnel
Railway Vikas Nigam Ltd undertook this project and PCM Strescon Overseas Venture Ltd were subcontracted the work for the ballastless track installation. The tunnel cuts through the Easter Ghats Mountain range and serves the purpose of connecting the newly developed Krishnapatnam Port to the rest of the South India. It is a freight line, which helps in bringing goods back and forth from Krishnapatnam Port.
Figure 3 : Finalized and Inaugurated RHEDA 2000® track at Rapur Tunnel Portal
The inauguration of this line has reduced the added travel distance by over 150 km and will be saving the Government of India over 500 crore rupees a year.
Rapid installation of the RHEDA 2000® ballastless track system across China, be it freight lines, mainlines, metro or light rail demonstrates the possible rapid growth in infrastructure and mobility of the country. Ballastless tracks with their high durability and longevity meet extraordinary demands of large and dense populations like India or China, also as the allowable travel speed is higher, thereby improving mobility in between cities.
About the PCM RAIL.ONE Group :
The PCM RAIL.ONE Group has been manufacturing concrete sleepers and track systems for urban transit and long-distance rail transportation for over 60 years. The technology leader also offers its expertise in the fields of engineering and plant construction. Its customer-driven innovations fulfill the highest quality standards and are installed around the world.
The PCM RAIL.ONE Group is comprised of several companies and eleven production facilities with a presence in Germany, Romania, Saudi Arabia, Spain, South Korea, Hungary, Turkey, the United States, and India. It maintains annual capacities of over 5 million track sleepers and 930,000 linear meters of turnout sleepers. RAIL.ONE produces optimized products and custom solutions with over 800 employees around the world.
Authors :
- Saurav Mittal (Director of Sales and New Projects) , PCM RAIL.ONE AG
- Arnold Pieringer (Senior Engineer R&D) , PCM RAIL.ONE AG
