The MAX Red Line is a light rail service in Portland, Oregon, United States, operated by TriMet as part of the MAX Light Rail system. An airport rail link, it serves 26 stations from Portland International Airport through Northeast Portland and Portland City Center to central Beaverton. The Red Line operates a 5.5-mile (8.9 km) segment of MAX from Portland International Airport station to Gateway/Northeast 99th Avenue Transit Center. From there, it interlines with the Blue Line and partially with the Green Line through to Beaverton Transit Center. Service runs for 22 hours per day with a headway of 15 minutes during most of the day. The Red Line is the second-busiest service in the MAX system with an average 10,310 passengers per weekday in September 2021.