Track geometry car

London Underground 1960 Stock Track Recording Train at Notting Hill Gate tube station
Track geometry car in Russia
Track geometry car in New York City
Federal Railroad Administration track geometry cars DOTX-218 and DOTX-220 are pulled along a BNSF mainline by a BNSF GE ES44C4 locomotive.
Holland Trackstar[1] in Washington Mills, New York

A track geometry car (also known as a track recording car) is an automated track inspection vehicle on a rail transport system used to test several parameters of the track geometry without obstructing normal railroad operations. Some of the parameters generally measured include position, curvature, alignment of the track, smoothness, and the crosslevel of the two rails. The cars use a variety of sensors, measuring systems, and data management systems to create a profile of the track being inspected.