The inclusions in BNbRE heavy rail steel were studied.By using DIL402C thermal expansion equipment,the thermal expansion coefficient of BNbRE heavy rail steel was analyzed.By using formastor-digital automatic phase transition analyzer,the phase transition temperature and microstructure was analyzed during cooling of BNbRE heavy rail steel.The results show that MnS inclusions' ratio of the length and width is small in BnbRE steel,and the formation of complexes of rare earth and silicate inclusions happen;whe...