"FRA Inspection Train at Greenport"
One of the Federal Railroad Administration's several inspection railcars pays a visit to Long Island Rail Road in the form of DOTX #216. This car made trips on all of LIRR's lines, testing all main tracks. This day (10/1/19) they covered LIRR's Main Line to Greenport. A father and his son take a break from a bike ride to view the train as it lays over at Greenport Station, which is the most eastern point on the Main Line.
Below is a more detailed description of the car provided by the FRA:
"The DOTX216 is a converted Amtrak Metroliner coach equipped with a track geometry measurement system, a rail profile measuring system, a multi-car ride quality measuring system, and other state-of-the-art instrumentation for conducting railway research. DOTX216 is capable of making track measurements at speeds up to 165mph and serves as a high-speed track research instrumentation platform for a variety of tests and research projects in the Office of Research and Development. DOTX216 is also used to support efforts undertaken by the FRA's Office of Safety."