On Sunday night, she boarded a sleeper coach in Mayurbhanj for Cuttack, a town adjoining the capital.
Around 3am, as the passengers slept, Hembrum, allegedly climbed up to the sleeper section, gagged her mouth and raped her.
The woman told the police Hembrum threatened to kill her if she raised alarm.
The woman reported the crime to the police after reaching Cuttack.
“Hembrum was arrested on the basis of the woman’s complaint and medical examination report,” Cuttack women’s police station inspector in-charge Sujata Jena said on Tuesday.