The conversion of Stuttgart’s old terminus into an underground through station is one of Germany’s biggest construction projects. The main design feature of the new station is its roof in white exposed concrete. This roof is supported by chalice-shaped columns. Its geometry was developed by Christoph Ingenhoven in cooperation with Frei Otto using soap skin and hanging models. An amazing project – but the complexity of the design and the difficult topological conditions present planners and contractors with completely new challenges. Project manager Angelika Schmid and CEO Roland Bechmann from Werner Sobek AG use the example of the chalice-shaped columns to explain how the interaction between design, planning and implementation was managed – and what role engineering played in this.