Abstract: The invention relates to a measuring system (1) and a method for measuring a wear condition of a contact element (32) of a contact strip (3) for a catenary-bound power supply of vehicles with a sensor device (4), the contact strip (3) having a contact strip carrier (31) and the contact element (32) held on the contact strip carrier, and at least two drill holes (5, 6, 7, 8) being introduced in the contact strip (3), the drill holes (5, 6, 7, 8) passing through the contact strip carrier (31) and forming at least one blind hole (51, 61, 71) in the contact element (32), the sensor device (4) of the measuring device (1) being detachably fastened outside of the contact strip (3) and below the contact strip carrier (31), an optical radiation being able to be registered by means of a photodetector (52, 62, 72) of the sensor device (4), and at least one drill hole (5, 6, 7) of the at least two drill holes (5, 6, 7, 8) forming a light channel upon reaching a certain wear condition of the contact element (32), the opti