This is so cool. From the Matrixsynth blog posting about “Conductor:”
Conductor turns the New York subway system into an interactive string instrument. Pulling from the MTA’s actual subway data, trains pluck at intersecting lines. The piece begins in realtime by spawning trains which departed in the last minute, then continues accelerating through a 24 hour loop. The visuals are based on Massimo Vignelli’s 1972 diagram.