This example visualizes railway routes and contour lines in Canada’s Rocky Mountains using a custom d3.js rendering. Geographic data from a TopoJSON file is projected and drawn with SVG paths. The railway is emphasized with an animated, patterned stroke that suggests movement along the track, while contour lines provide topographical context. The visualization uses d3.v4 to load and process the JSON topology, compute the projected paths, and apply the railway symbology, resulting in a stylized map that highlights the route’s relationship to the terrain.