Frankfurt Airport has two train stations - one for suburban and regional trains and one for long distance/inter-city trains.
The Frankfurt Airport Regional Station is located below Terminal 1. S-Bahn train services S8 and S9 link the airport with central Frankfurt at Hauptbahnhof (central) station.
Trains run approximately every 15 minutes with a journey time to/from Frankfurt Hauptbahnhof of around 11 minutes.
The first train to the airport departs Frankfurt Hauptbahnhof at 04:17, the last at 00:47.
The first train to Frankfurt Hauptbahnhof departs the airport station at 04:32, the last at 01:32.
The fare between Frankfurt Hauptbahnhof and the airport is €3.80.
Online S-Bahn service information is available here.
The AIRail Terminal inter-city train station is linked to Terminal 1. Deutsche Bahn has services to many German cities including Cologne and Stuttgart.
More information on Deutsche Bahn services is available online.