Patrons on board the Millbrae bound train reported that a male suspect was on board acting erratically, holding a large knife. The suspect was described as a white male in his 40's, with a buzz haircut, wearing a gray jacket with silver stripes on the sleeves. The suspect off-boarded at Orinda Station. Officers, along with Orinda PD responded and detained the man on the platform. No complainants came forward, but officers determined that the man was intoxicated in public. A kitchen knife was found on top of a fire cabinet near the suspect. The man was arrested for public intoxication and was booked at the Martinez Detention Facility.