SideTrack and MotionPoster utilize similar technologies that essentially turn train passengers into projectors, and train windows into lenses. How? Light boxes, each one simulating a single frame, are placed inside the tunnel. As the train travels through the tunnel with the passengers looking out the window the succession of light boxes is transformed into a ‘movie.’

According to the NYT, the tunnel advertising is part of New York City’s Metropolitan Transportation Authority plan to convert real estate into advertising space. They also plan to sell space on turnstiles, digital screens inside stations, projections against subway station walls, and panels on the outside of subway cars.