Innovation in the Dutch railways in the domain of capacity management and traffic control is increasingly difficult to implement because of the large interconnectedness of all processes and separation into different institutions and organizations. Meanwhile there is a push for quality improvements leading to more robustness and resilience as well as a significant capacity increase. In the years 2009 - 2010, the gaming group of Delft University of Technology was asked to introduce gaming simulation methodology at ProRail, the Netherlands’ rail infrastructure manager, to support innovation projects. Three initial trial projects ran so successful that the organization asked the Delft researchers to identify where in the organization large-scale implementation of gaming simulation methodology would be most promising. Based upon a series of interviews through the organization, ProRail and TU Delft jointly formulated a four-year research and implementation proposal that is now in operation. The first gaming session in this new collaboration proved the essence of the fit of gaming simulation for innovation at the Dutch railways. Unique for gaming simulation is the highly detailed simulation of both the more technical and process variables of rail infrastructures as the decision and communication function of real people in their real roles. The method does not assume models of decision-making but draws upon the real-world knowledge of professionals in the operation. The paper gives lessons learned on methodological challenges resulting from the four projects described.