Complex sentence: Baar railway station is a stop on the InterRegio service between Zürich Hauptbahnhof and Lucerne, serviced every full hour, as well as on the Zurich S-Bahn service S21 between Zug and Zürich Hauptbahnhof.
Split into simpler sentences: Baar railway station is a stop on the InterRegio line between Zürich Hauptbahnhof and Lucerne, serviced every full hour. It is also a stop for the S-Bahn Zürich on the line S21 between Zug and Zürich Hauptbahnhof.