We identify and quantify the impact of subways on equalising academic achievement in an urban school choice setting. Specifically, we study the short- and medium-term effects of a massive subway network expansion in Chile on the academic achievement gap between low- and high-performing students. Estimates are derived using fixed-effects models. Closer proximity to the subway network is associated with the equalisation of academic achievements. In the medium-term (3 years after the opening of the subway stations), the gap between low- and high-achievers decreased by 5% of a standard deviation.