Complex sentence: Trams on each line run at frequencies that vary between 4 and 8 trams per hour, depending on the day and time of day, combining to provide up to 16 trams per hour on the common section.
Split into simpler sentences: Trams on each line run at frequencies that vary between 4 and 8 trams per hour, depending on the day and time of day. These services combine to provide up to 16 trams per hour on the common section.