This unit is used to repair ways. It works more or less independently from speed and self-centres on the way. Adjustment angles and working width can be at anytime adjusted in order to correct the result. The rotary axes of the signs, the axes of the inclination adjustment of the signs, the main rotary axis respectively connecting axis from the roller to the frame and the rotation axes of the roller have been realized with plastic plain bearings from igus®. Compared with conventional bearings, they perfectly manage the dirty and humid working environment and do not require lubricants.