Abstract: A laser apparatus for monitoring the rails of a railway or tramway line, characterized by comprising at least two measurement units mounted on a railway or tramway carriage and operating at last on the inner part of the two rails, along with said carriage is made to advance, and a unit for processing the signals transmitted by said measurement units, each of which comprises at least one triangulation reading device.

Abstract: An apparatus for measuring the characteristic parameters of an overhead railway or tramway line, characterized by comprising, on board a railway or tramway vehicle (25): at least one laser source (2) for generating a laser beam, optical means for transforming said laser beam, generated by said soruce (2), into a flat beam (4), means for orientating the axis of said flat beam (4) at an angle other than 90° to the axis of the overhead line wire (6) and defining with this latter a plane substantially perpendicular to the plane of said beam (4), at least one video camera (8) having its optical axis different from the axis of said flat beam but lying in said perpendicular plane and orientated towards the light-emitting line of intersection of said laser beam (4) with said wire (6), the apparatus also comprising a processing unit for the signals generated by said video camera (8) in order to determine the position of said light-emitting line within the optical field of said video camera (8), and to effect r