Automatic systems for wear measurement of contact wire in railways

Measuring systems that detect automatically the degree of wearing of the contact wire in railways are necessary in order to carry out an efficient infrastructure management and maintenance based on contact wire condition. This paper describes automatic methods to measure the wear of overhead wires, in particular, those based on optical detection techniques. Different automatic systems that measure the wear are outlined. The measuring basis of different approaches, type of illumination and optics used, acquire and processing procedures are studied. A comparative analysis of technical solutions adopted by each of them is shown and the major advantages and disadvantages are highlighted.