Contact wire wear on electric railroads

It is the purpose of this paper to present such data on the subject of contact wire wear as the electric operation of four railroads has made available. Design of overhead system and pantographs, lubrication of pantograph shoes, presence of steam locomotives under catenary, ice on contact wire, condition of roadbed, speed of trains, and amount of current collected at pantograph shoe all have a bearing on the rate of wear, the relative importance of each of these factors being a moot question. The four railroads contributing are the New York, New Haven and Hartford, the Chicago, Milwaukee, St. Paul and Pacific, the Pennsylvania, and the Illinois Central.