Rail related infrastructure projects, like many projects, often fail to deliver within budget and time. The root cause of most failures however is not technical, but rather, managerial. The existing scientific literature reveals that the impact of unexpected events in the project is a major contributor to these overruns. There is not, however, a lot of usable knowledge on how these events can be managed in order to help project managers better perform their function. This research, which comprises an extensive literature research and the analysis of three rail related projects, contributes to this gap by offering key learnings on different types of unexpected events, and providing insight into five underlying mechanisms that lead to major problem areas in rail related infrastructure projects.