During the weekend of June 16-19, 2017, Amtrak engineering forces work to replace three full track panels (ties, rail and switches) in "A" interlocking, an area of tracks and switches that serves as the crucial sorting mechanism routing trains that enter Penn Station from the Hudson River tunnels and the Long Island Rail Road’s West Side Yard to the various tracks and platforms in the station. This time-lapse video captured just over 22 hours of a 55-hour work period.