Are there storage lockers at the Zurich train station? If so, where?
Yes, there are plenty of lockers there, on a mezzanine just below the main tracks (signage is good). There are lockers in all Swiss main stations and many secondary ones too; look up a station name on the SBB (Swiss Railways) website and you will find the info about locker availability plus a map of the larger stations including Zürich HB.
Older lockers need coins, but the ones in Zürich should be new by now and should take card.