You can take a folded scooter or e-scooter as hand luggage and stow it under the seat. However, vehicles with an internal combustion engine (moped, motorbike), tricycles, multi-seat recumbent bikes, Segway personal transporters, electric scooters and electric scooters are not permitted.

The best thing to do is to contact the SBB, they will be able to answer your question more precisely.