This visualization adapts E.J. Marey’s classic train schedule to show southbound Caltrain service from San Francisco to Gilroy. Each train’s path is drawn as a segmented line where slope represents speed, while color redundantly encodes the same information through a purple-to-orange scale. The code filters trains by type and uses D3’s time scale, linear scale, and SVG axis API to render the station grid and diagonal trajectories, with station stops marked as circles. Data is loaded from a tab-separated schedule file using `d3.tsv`.