FIELD: measurement.
SUBSTANCE: invention relates to method and measuring apparatus (19) for determining characteristics of rail head (5) surface along rail line (1) laid and formed by rails (2). Measuring car (16) and measuring unit (14) having at least one first measuring system (21) are provided. This first measuring system (21) includes measuring base holder (22), guide system (23) and at least one first sensor (24) located on measuring base holder (22). Holder (22) of the measuring base is installed with the possibility of relative movement by means of guide system (23), in the normal orientation relative to plane (13) of the rail defined by each rail (2), in relation to frame (17) of the car. Also, measuring base holder (22) together with said at least one first sensor (24) during movement of measuring car (16) on rails (2) by means of support device (26) mechanically rests on at least one of rails (2) and so is always directed longitudinally above rail (2) at a predetermined fixed distance from it.
EFFECT: as a result, a mobile measuring unit is created, through which the user can ensure reliable and constantly accurate positioning of said at least one sensor above the longitudinal rail profile during the measuring installation movement along the rails.
21 cl, 5 dwg
