The train station in Lausanne is filled with cameras that anonymously track people walking through its corridors. Used to estimate the congestion in the station, the analysis of average pedestrian trajectories is crucial to the improvement of the life of thousands of daily commuters. To do this analysis, we divide the train station into small regions of around one square meter linked together if they are adjacent on the ground. Using more than 42 million pedestrian positions, we determine when a region is sufficiently crowded at a given time and record the propagation of the congestion on the network. It yields to the creation of thousands of disconnected sub-networks, here colorized on the image. If you have ever been to the Lausanne train station, your trajectory is probably contained in what you see!