Abstract: A track maintenance machine for carrying out track position corrections includes a machine frame movable by on-track undercarriages on rails of a track and a track position measuring system having two outer measuring devices and a central measuring device with a common reference base, relative to a longitudinal direction of the machine. The measuring devices are defined in their position relative to the rails. Two mutually aligned measuring chords are tensioned or stretched as a reference base between the outer measuring devices. The central measuring device includes a measuring transducer for detecting position data of the two measuring chords. The position data are fed to an evaluation device in order to determine a longitudinal level for each rail and a versine. Thus, two measuring chords are sufficient to detect all of the track parameters. A method for operation of a track maintenance machine is also provided.

Abstract: A terrain profiling apparatus for quick and inexpensive profiling of relatively large areas of ground. A prime mover pulls a sled across a terrain to be profiled. A gyroscope on the sled indicates slope and a measuring device records distances moved. Slope and distance signals are used by a computer to indicate terrain profile.