No objection certificate (NOC) for Railway staff appearing in State Government selection

Sir, i am working as junior engg.(GP 4200) in RLy. from July  2001 and my rate of pay 17640/.i want to appear in state govt. JE(GP 4200) exam and if i am selected i want to join in state govt. je post.Does Railway give No objection certificate for this post. What is the complete process please clarify .
Thanking you sir.