This study aims to analyze the effect of training, career development and human relations on the performance of machinists in PT.Kereta Api Indonesia (Area Operation V Purwokerto). This type of research is quantitative research. The research sample of 162 machinist respondents using purposive sampling techniques and data obtained directly from respondents with the research instrument using a questionnaire. The data obtained were then analyzed using a descriptive test, a research instrument test, a classic assumption test, a multiple linear regression analysis test and a model adequacy test. The results of the research partially showed that training had a significant effect on performance, career development had no significant effect on performance and human relations had a significant effect on performance. While the results of the study simultaneously showed that the variables of training, career development and human relations affect performance.