Passengers' Safety First

Shanghai, February 5, 2015. Ensuring passenger safety and comfort are the main criteria in rail traffic today. In 2013, the total length of China's high-speed railway surpassed every other comparable national system in the world. And it continues to grow. One of the technological challenges faced by the system's designers has been to maintain the suspension function of carriages at extreme low temperatures for example in North China. High-speed trains operating in the north of China in particular place significant demands on the rubber and metal components of the carriage bogies. The Freudenberg Group has successfully developed an innovative low temperature compound solution that plays a vital role in putting passenger safety and comfort first on the Chinese railway system.

Significant mileage and sizeable strains sustained by trains constitute the most rigorous demands made on the function and service lifetime of vibration control components. Systems and components from Freudenberg Schwab, a Freudenberg Sealing Technology business division, reduce vibrations and noise to safeguard people, materials and the environment.

Freudenberg's new low-temperature rubber compound is already in use on the Harbin-Dalian high-speed railway. This was China's first railway of its kind and is also the world's first high-speed railway to operate in extreme low temperature areas. This part of China regularly sees winter temperatures drop to minus 40? and sometimes even lower than that. The rubber to metal parts applied on bogies is crucial to reduce the vibration and absorb the impact, ensuring passenger safety and comfort. It has to function properly with good endurance especially under low operational temperatures. Today, comparison testing has clearly demonstrated that the new low-temperature rubber compound developed by Freudenberg maintains the same levels of durability as natural rubber compounds, even at such extremes of cold.

As rubber approaches its "glass transition" temperature, the stiffness of the component rapidly increases until the material no longer provides any vibration damping at all. To prevent this situation, the lowest operating temperature needs to be approximately 5-10°C higher than the glass transition temperature. The low temperature limit of natural rubber is -40°C. Until recently, optimizing the low-temperature performance of rubber compounds always came at the cost of reduced durability.

Freudenberg Schwab eagerly took up the challenge. After years of continuous research and development, the company successfully developed a low-temperature rubber compound capable of meeting these extreme requirements. The compound can withstand temperature as low as minus 50°C.

China currently has over 10,000 km of high-speed railway in operation and a further 12,000 km are under construction. By 2020, according to the government's long-term plan, China's high-speed railway network will exceed 16,000 km and will connect all provincial cities of over 500,000 inhabitants, accounting for 90% of the country's populous territory.

"This ambitious plan is a reflection of our commitment to improving the service that passengers enjoy, making high-speed rail travel safer and more comfortable", commented Sadok Sahmimi, General Manager of Schwab Vibration Control. "We focus on innovation and optimized solutions for different markets around the world. We are ready with the technology needed to achieve the Chinese government's goals."