Transport and Technology Dept.
Railway Operations Headquarters,
Japan Freight Railway Company
Engineer, Strength Evaluation and Inspection
Vehicle Technology Development Division
Technological Development Department, RTRI
Chief-Engineer, Railroad Vehicle Group,
Roller Bearing Technology Dept.
Bearing Engineering Center, NSK Ltd.
Lead base white metals have been used for journal plane bearing of freight cars for a long time in Japan. Lately, an alteration of base material from lead to tin was discussed to improve working environments. Specimens and full-size bearings were tested to compare the scuffing resistance of these metal materials including running performance tests by freight cars. WJ-2, one of the tin base white metals, has a better scuffing resistance than lead base white metals WJ-7. The scuffing load is reduced remarkably, however, by an increased roughness and/or waviness of journal surface. Therefore, scuffing resistance of journal plane bearings is improved noticeably by a combination of WJ-2 material and properly machined and finished journal.