Sandwich materials, consisting of two thin facings separated by a low density core, can be used to produce structures that are both light and stiff. They also offer opportunities for parts reduction through design integration, improved surface finish and lower assembly and outfitting costs. DE-LIGHT Transport aimed to further promote the use of sandwich materials by developing key technologies to support the practical realisation of robust sandwich designs. Specifically, this included:    The development of a multi-material sandwich design tool. Previous work has often focussed on a particular type of sandwich construction (e.g. laser-welded steel or composite). This has tended to yield niche results with limited applicability. DE-LIGHT Transport has implemented a more generic design approach that allows the evaluation and optimisation of a wide range of material and structural mixes according to the requirements of a given application    Strategies for joining, assembly and outfitting – the bringing together and integration of separate sandwich panels and/or sub-components to produce finished structures. In particular, modular approaches for the off-line production of sandwich assemblies to exploit economies of scale have been developed    Testing and validation procedures – to provide accurate and reliable methods of determining fitness for purpose.    The above technologies were demonstrated within the project through the design and manufacturing of six prototype structures. These included deck and deckhouse structures for ships, a rail vehicle cab, and a freight container. Risk-based design principals were applied throughout to ensure that the new designs comply with existing regulatory frameworks.NewRail’s major contribution to the project was the design of a lightweight crashworthy rail vehicle driver’s cab based on sandwich material technology.