Hello Dejeawhea46
Travelling with a tandem bicycle on Swiss trains is a challenging undertaken, as the space to transport this bulky vehicles is often not given. For this reason, on SBB trains, you are allowed to take them on RE, R, and S trains.
You can find the train category when you look up the timetable on www.sbb.ch/en. For example, RE48, or S2.
Also, in the Zurich area, you cannot transport bicycles, not even on R, RE, and S trains during the rush hour, from Monday to Friday 6–8am and 4–7pm.
Thus, to see all possible trains, go to https://www.sbb.ch/en, click on Settings, and activate the Means of transport option, and deselect all service types but S/SN/R, and RE. Furthermore, activate the setting Bicycle transport.
The timetable will only offer connections that are possible respecting these settings.

Let us know if you need more help.
Kind regards,
Roland