This abridged case, the third in a series that begins with “Design Thinking in Action (A): South Western Railway” (UVA-S-0377), describes two waves of experimentation undertaken by UK railway operator South Western Railway (SWR) and its design-consultancy partner, David Kester & Associates (DK&A), during the deliver stage of their joint project to improve customer experience at SWR. They had followed a classic design thinking methodology, discovering customer experiences and needs, defining journey maps and personas, and developing concepts. In this final case, they tested those concepts in actual rail stations to determine whether they met goals for desirability, feasibility, and viability. For those interested in adding self or peer assessment to students’ design thinking learning journey, Professor Jeanne Liedtka, working with coauthors Karen Hold, Jessica Eldridge, and Treehouse Design, has synthesized more than a decade of research at Darden to create the Innovation Impact Assessment. This tool will help students identify personal development opportunities and provide them with practical guidance (in the form of detailed individual feedback reports) to accelerate skill development. The instrument identifies a set of five core competencies based on 44 behaviors that successful design thinkers have in common. It is available for individual use and bulk purchase via Darden Business Publishing at this link: https://store.darden.virginia.edu/innovation-impact-assessment.