Early Wednesday morning, a driver on Jefferson Street got onto the MAX tracks and continued driving into the Westbound tunnel about 200-yards before stopping.
Special lift equipment was needed to remove the car from the tracks.
TriMet started the morning by alternating trains east and westbound on the eastbound tracks, but by 7 a.m. when passenger delays became too long TriMet switched to buses to shuttle passengers around the closure.
Police arrested 28-year-old James Dejarnette for DUI and Reckless Driving.
Service was finally restored around 9 a.m.