Building Lightweight Trains (IMAGE) Fraunhofer-Gesellschaft Caption Although this diesel engine housing for trains is made of a light polyurethane-based material, it is nonetheless capable of withstanding extreme stresses. Credit Fraunhofer ICT Usage Restrictions The picture may be used for editorial purposes only. It is protected by copyright. The use is free of charge if the reference is mentioned. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.