Striving to Set New Records

China has one main motto when it comes to expanding its gigantic railway network: High Speed. But the window glass used in these super express trains also needs to be able to stand up to this. A job for SCHOTT® LAS80.

The slim CRH 380 type train raced along the Chinese high-speed rail route between Shanghai and Hangzhou that has not officially been opened yet at a speed of 486 kilometers – a new speed record for conventional passenger trains. One month later, China’s state railway continued to hurry things along. The rail ministry announced that the 1,300 kilometer prestige route from Beijing to Shanghai would be opened already in June of 2011, months earlier than planned. The ministry also said the rail network for high-speed trains would be expanded by nearly 5,000 kilometers to reach more than 13,000 by the end of the year. This year’s investment plans for railway construction were esimated to be 700 billion yuan (80 billion euros) – nearly as much as in 2010. Today, China already has the fastest trains and longest high-speed rail network in the world (see also p. 11). However, its motto isn’t just high speed, but also high-tech. The Middle Kingdom has even managed to become the global leader in the area of rail technology. In past years, a lot of technological know-how no doubt flowed from the west to the east, as express train platforms were imported from Europe and Japan. Today, however, China is developing and building more of its super express trains on its own. The challenge now facing Japan’s Shinkansen, France’s TGV or Germany’s ICE goes by the name CRH (China Railway Highspeed). Chinese companies like CSR Sifang Locomotive & Rolling Stock or cnr Tanghsan Railway Vehicles now manufacture trains that reach speeds of 400 kilometers per hour and more under this name.

Such high speeds require that special safety precautions be taken and that technology that is capable of standing up to these extreme conditions be used. It all starts off with special tracks that can handle high speeds of at least 200 kilometers per hour, but also includes an equally high-performance train control and security system. Factors like lightweight construction, electric drives, smoothness, adhesion of the wheels to the tracks, including power transfer, air resistance and noise development all play key roles in building super express trains.

The strains that train glazing is exposed to shouldn’t be under­estimated either. These include sudden shifts in pressure when entering or leaving a tunnel or encountering a train that is traveling in the opposite direction inside a tunnel. These differences in pressures would cause uncomfortable shifts in pressure or even hearing impairments and unconsciousness for passengers and the train crew if special highly resistant glasses and protective systems were not used. Objects or animals that hit the windshield pose yet another threat. At speeds of several 100 kilometers an hour, their impact is similar to that of a bullet.

Conventional flat glass laminates are unable to withstand these loads or simply too thick and heavy to be used in the super express trains designed to be lightweight. Not SCHOTT® LAS80, however. This lithium aluminosilicate glass is manufactured using the microfloat process and then chemically cured. Thanks to the sophisticated process know-how that the manufacturing site in Jena, Germany, has in the area of post-treatment, it takes on very high fracture toughness, scratch and pressure resistance, as well as extremely high breakage strength that is up to five times higher than that of conventional flat glass. Therefore, it is highly resistant, even when it is very thin, as special tests have shown. In the so-called Rock Strike Test, a laminate that consisted of three LAS80 panes with a total thickness of six millimeters stood up to being bombarded with a sharpened 20 g bullet made of aluminum that was shot at the glass at a speed of 500 km/h without being damaged. The amazing thing was that while the shock caused by an aluminum impactor that weighed a kilogram and traveled at a speed of 450 km/h broke the glass, it was unable to penetrate through the 6 mm laminate.

These qualities also convinced the Chinese company Haian that equips super express trains with special glazing. Here, the processing company benefited from yet another advantage: the low transformation temperature of SCHOTT® LAS80 makes it easier to produce complex 3D shapes and thus offers greater freedom of design. In the meantime, Chinese super express trains are already on the move with six or eight milli­meter thick LAS80 insulating glass units as front and side windows. These include not only the CRH 2 and 3 model trains, but also the faster 380 series that covers both the routes from Shanghai to Beijing and the record route Shanghai to Hangzhou.

More speed records are certain to follow. According to press reports, state-owned laboratories are already working on trains that will be able to travel at speeds of up to 600 kilo­meters per hour. That sounds like good news for SCHOTT, too: ”We expect to see a constant flow of business,” says Dr. Lutz Wehmeier, General Manager of Sales & Marketing for SCHOTT Technical Glass Solutions in Jena. Business that also includes lightiFor several years, the railway network in China has been growing at a breathtaking pace to include approximately 91,000 kilometers at present. It is expected to encompass 120,000 km, more than 18,000 of which will accommodate super express trains, by 2020. Between 2005 and 2010, China invested 1.98 trillion yuan, or around 226 billion euros. The next five-year plan that leads up until 2015 includes an even larger amount. The high-speed rail network, at 8,358 kilometers already the longest in the world at the end of 2010, is of immense importance in this respect. This is how the world’s second largest economy is seeking to ensure that their workers can span long distances much more quickly. After all, companies here need to build more sites further inland, where land and skilled workers are even more readily available and affordable than on the expensive, urbanized east coast. For this reason, trains that travel as fast as lightning will connect important transportation hubs in all directions. Then, the passengers who take the 1,318 kilometer route from Beijing to Shanghai that will open soon will only have to travel for five hours or half as long.