Measuring device for ascertaining the position of a contact wire of an overhead contact line system assigned to a track relative to a rail vehicle travelling on the track, comprising - a time-of-flight camera arrangement arranged on the rail vehicle for detecting image data with depth information of a capture region containing the contact wire, - wherein the time-of-flight camera arrangement has a plurality of time-of-flight cameras (11, 12, 13, 14), characterised in that - each time-of-flight camera (11, 12, 13, 14) has a sensor arrangement with a matrix-type arrangement of sensor pixels, - wherein in order to reduce the recording time for high travel speeds of the rail vehicle, the number of rows of sensor pixels to be read out can be adapted, - wherein the time-of-flight camera arrangement - comprises a first time-of-flight camera, which is arranged in the centre of the vehicle and has an optical unit with a vertical optical axis and with a focal length for capturing contact wires, which run in a close, lower section of the capture region, - comprises a second time-of-flight camera, which is arranged in the centre of the vehicle and has an optical unit with a vertical optical axis and with a focal length for capturing contact wires, which run in a remote, upper section of the capture region, and - comprises a third time-of-flight camera and a fourth time-of-flight camera, which are arranged in symmetry outside of the centre of the vehicle and have an optical unit with optical axes (A3, A4) tilted outward about an acute angle with respect to the centre of the vehicle and with a focal length for detecting contact wires, which run in lateral edge regions of the close, lower section of the capture region, and - wherein the measuring device comprises an evaluation unit, which is embodied to estimate position data of the contact wire using different estimation methods and to determine the relative position (X, Z) of the contact wire by spatial and temporal fusion of the position data. - a time-of-flight camera arrangement arranged on the rail vehicle for detecting image data with depth information of a capture region containing the contact wire, - wherein the time-of-flight camera arrangement has a plurality of time-of-flight cameras (11, 12, 13, 14), characterised in that - each time-of-flight camera (11, 12, 13, 14) has a sensor arrangement with a matrix-type arrangement of sensor pixels, - wherein in order to reduce the recording time for high travel speeds of the rail vehicle, the number of rows of sensor pixels to be read out can be adapted, - wherein the time-of-flight camera arrangement - comprises a first time-of-flight camera, which is arranged in the centre of the vehicle and has an optical unit with a vertical optical axis and with a focal length for capturing contact wires, which run in a close, lower section of the capture region, - comprises a first time-of-flight camera, which is arranged in the centre of the vehicle and has an optical unit with a vertical optical axis and with a focal length for capturing contact wires, which run in a close, lower section of the capture region, - comprises a second time-of-flight camera, which is arranged in the centre of the vehicle and has an optical unit with a vertical optical axis and with a focal length for capturing contact wires, which run in a remote, upper section of the capture region, and - comprises a third time-of-flight camera and a fourth time-of-flight camera, which are arranged in symmetry outside of the centre of the vehicle and have an optical unit with optical axes (A3, A4) tilted outward about an acute angle with respect to the centre of the vehicle and with a focal length for detecting contact wires, which run in lateral edge regions of the close, lower section of the capture region, and - wherein the measuring device comprises an evaluation unit, which is embodied to estimate position data of the contact wire using different estimation methods and to determine the relative position (X, Z) of the contact wire by spatial and temporal fusion of the position data.