Ten Axles.
New York City Transit Authority (NYCTA) TGC3, one of the Transit Authority's two Track Geometry Cars, is seen at 231 St station in the Bronx, returning from a geometry run up to 242 St. The car is not taking measurements at this point, which is evident by the halogen lamps on the front being off and the red laser scanner under the trailing unit being absent. This is likely due to the time of its run: it came up measuring the middle track during the tail end of morning peak, so it had to run back down quickly to avoid delaying any revenue trains - measurement requires it to run at a slower speed.
One of the many unique features of the TGCs is their axle count; unlike a typical two-car pair, they have 10 axles. The middle two on the first unit are used for measuring track geometry parameters including loaded gauge and curvature.
