The detecting and the singal of freight train rolling bearing are special so the diagnosis knowledge is obtained by means of data mining technology. Build up fault case database. By fuzzy method, fault cases in the database are chustered. Using cut-off set of fuzzy matrix, gets the definite classes of fault cases. The objective function of clustering ratio of correct fault cases to all fault cases is built. It directs the data mining of fault cases so that the sensitive information sources, the vectors of p...