Passenger safety is a key requirement in the public transport sector, but the interiors of train and subway carriages, trams and buses also need to be protected against the wear resulting from frequent use, not to mention the damage caused by vandalism.
Rail operators and other public transportation companies are therefore increasingly insisting on highly robust materials for interior applications. At the Innotrans trade fair from September 21-24, 2010 in Berlin, Bayer MaterialScience will be showcasing innovative solutions using sheets made from the polycarbonate (PC) Makrolon® and the PC+ABS (acrylonitrile-butadiene-styrene) blend Bayblend®. These highly versatile products ensure the safety and durability of public transport interiors. They can also be used for effective yet attractive noise protection along freeways and rail tracks.
Passenger trains in particular are a frequent target for vandals, who take great delight in scratching windows, spraying graffiti and trashing seats. They are also subject to natural damage resulting from the effects of high or low temperatures. Any repairs required can impact on the availability of rolling stock and thus result in additional costs. Using sheets of Bayblend® could prevent damage of this kind and the availability problems that ensue. The material combines excellent break and shatter resistance with high impact resistance, even at freezing temperatures. It also effectively withstands violent mechanical impacts. The excellent surface quality of the sheets makes graffiti easy to remove using a water hose.
The development phase for the semi-finished products is already nearing completion. As Wim Van Eynde, global project manager for mass transportation in the polycarbonate sheets section at Bayer MaterialScience, explains: “Our product is already being used with great success in other countries, for example in Dutch trains, where the benefits of these applications have been demonstrated to impressive effect. The market launch in Germany is scheduled for the end of this year.”
Bayblend® sheets for use in rail vehicles are produced by thermoforming, which saves on mold construction costs and offers designers a great deal of scope for creative freedom. After all, train interiors should look good in addition to being safe. The thermoplastic material is ideal because it allows easy processing and forming, and is lightweight yet extremely robust.
It is therefore also being lined up for future glazing applications as a replacement for glass, which is much heavier and breaks easily. This is where the benefits of Makrolon® really come into their own. “The sheets are virtually indestructible, which eliminates the need for repair work and the resultant service cancellations. Transparent polycarbonate also matches the optical qualities of glass,” stresses Van Eynde.
The solid sheets’ fire performance is also worthy of mention. The products which are currently being developed could meet the stringent requirements of European fire safety standard EN 45545 for applications in train interiors.
18 millimeters for efficient noise protection
Bayer MaterialScience is also keen to make greater use of Makrolon® with all its benefits in noise protection applications. It is currently developing a polycarbonate sheet 18 millimeters thick that can cut noise levels by 36 decibels (dB) – significantly more than the 28 dB reduction stipulated by the legislators. Noise protection walls can be installed along both freeways and rail lines. “Noise is a key issue that affects a great many people,” explains project manager Fabrice Albrechts.
The sheets have already passed initial tests – including impact, stone impact and fire tests – with flying colors, but further development stages are required for rail transport in particular. “High-speed trains have a huge dynamic impact on noise protection walls. Consequently, DB Netz AG has set out special requirements and the material is currently being tested to ensure it meets these,” explains Albrechts.
Transparent noise protection walls made from Makrolon® have already proved successful in other countries. Unlike dark concrete tunnels or other opaque materials, they give drivers and their passengers an unrestricted view of their surroundings at all times. Where light passes straight through the transparent walls, plants and greenery flourish, too. As a result, walls of this kind are assimilated much more effectively into their surroundings. What’s more, sheets that have reached the end of their service life can simply be reused. The material is 100 percent recyclable.