Frankfurt(M) Flughafen Fernbf on the sites of the railway company. Signs posted throughout FRA call it "Fernbahnhof" and "Long-distance train station."

5 min walk from T1. From T2, add an ~8 min bus ride + wait time. There is a bus from T2 going directly to the station. But can also take the bus T2 -> T1 and walk to the station from the T1 bus stop, takes a little over 5 min.