Train from Zurich HB to Grindelwald - is there food that can be purchased?

Yes to both.

I like the pretzel king for sandwiches.

https://www.flughafen-zuerich.ch/en/passengers/shopping-and-enjoy/eat-and-drink/all-food-and-drink/brezelkoenig-airside

https://brezelkoenig.ch/de/sortiment/produkte

There is also a Coop grocery store near the train station. Pick up some paprika potato chips.

https://www.flughafen-zuerich.ch/en/passengers/shopping-and-enjoy/shops/all-shops/coop

Carrie, maybe you could start a paprika chip franchise in Chicago?! ;) You would be wildly successful, and could retire and travel full time!

The Coop Naturaplan paprika potato chips and Naturaplan organic paprika tortilla chips are so addictive. We keep way too many bags in our chalet over the summer :)

Mmmm sounds like I’ll need to go out of my way to find some.

I did want to clarify though that I meant Zurich HB to Grindelwald. I do see that Zurich HB has plenty at the station. Just want to be sure there stuff on the train.

IC trains generally have restaurant cars, Your best train would be the IC 81 that is direct all the way to Interlaken Ost. It goes at 7:02 am and at 2 minutes past the odd hours (9:02, 11:02, etc). You can even purchase seat reservations in the restaurant car. There is nothing in the short train ride from Interlaken Ost to Grindelwald.

IC trains at other times require you to change trains in Bern or Spiez, They have restaurant cars as well, but the onward connecting trains probably not.

https://www.sbb.ch/en/travel-information/services-on-train/sbb-restaurant-bistro.html