Small defects on a train track can have big impact on high-speed trains. However, as those defects are small, detecting and classifying them by visual inspection is difficult and time consuming. On the other hand, a train moving over small defects can shake significantly so we can measure train movements to detect track problems. In this talk, we will look at a short project I did in the Oxford Model Camp. We have a direct data extraction model and a forward model to understand how camera images can help us to understand the movement of trains. I will explain how images is formed how 3D objects is projected onto a 2D surface. There are a few nice videos to show how an old but useful algorithm - the Hough Transformation, can give us train tracks from videos.