Officers responded to the station on the report of a battery having occurred aboard a Dublin-Pleasanton train. The female suspect, for no apparent reason, punched a female victim on top of the head and pulled her hair. Based upon a suspect description, and her last known location, the officers managed to detain the suspect near the station. The victim positively identified the suspect and placed her under citizen’s arrest for battery. In addition, a warrants check revealed the suspect was wanted on an outstanding $5,000 battery warrant issued by the Santa Clara County Sheriff’s Office. The suspect was then placed under arrest for battery and the outstanding warrant. A sergeant responded to approve the arrest and debrief the suspect. The suspect was issued a prohibition order before being booked at the San Francisco County jail for misdemeanor battery and the warrant. The victim, who complained of pain, did not sustain any visible injuries, nor did she require medical attention at the scene.