Stains on Shell of Non-Coating Rolling Stock

Stains on the shell of non-coating rolling stock tend to be conspicuous when compared with rolling stock coated with paint. In some cases these stains sticking to metallic surface remain unremoved in a simple water washing process. In this investigation, an attempt was made to clarify the mechanism of stains. At first, the contents of stains on the non-coating rolling stock shell was examined and it was found that stains principally consisted of iron rust and iron compounds supposed to be the wearing powder of wheel and rail. From this finding, the method of accelerated staining with iron filings was developed. The stains of shell were reproduced on dry and wet cyclic environment tests after iron filings on the test specimen. For cleaning of these stains, normal and high viscosity cleansers were compared. The high viscosity one showed a good result for removing stains.