Lambert-St. Louis Airport by Train
The Metrolink light rail system operates between Lambert-St. Louis Airport and many city locations. Each terminal has its own train station.
The Terminal 1 station is located on the upper (Departures) level. The Terminal 2 station is through the parking garage.
The first train to the airport departs Union Station at 4.16 am, the last at 12.52 am, Monday-Friday. On Saturday and Sunday the first departure is 5.03 am.
The first train to downtown St. Louis departs the airport at 4.21 am weekdays, 5.08 am weekends. The last train departs at 12.57 am.
Trains run every 12-20 minutes throughout the day.
Fare: $4 one way, $7.50 for a day-long pass.
More information is available here.