This article examines how innovation can be strategically incorporated into transportation systems. Large transportation systems generally have a poor record in systematically integrating innovation in their development, construction and operation. Our research setting is Crossrail, a major new railway traversing London, where the creation and implementation of an innovation strategy formalized and systemized its approach to innovation. Based on in-depth, semi-structured interviews with project leaders and participant observation, the paper critically analyses the formulation, implementation and performance of Crossrail’s innovation strategy. Crossrail’s management explicitly uses an ‘open innovation’ strategy that incentivizes partners, contractors, and clients to innovate in the project. Its strategy guides decisions and priorities on innovation and the types and levels of innovation that best match project aims. The paper holds lessons for those developing, operating and studying large transportation systems both now and into the future.