Hi Boossinnuech57
Thank you for your request.
You can buy your train tickets just before departure at the station ticket office.
The express service is only offered for door-to-door luggage. For Luggage station to station, you drop off your luggage friday and collect them at St.Moritz on Sunday. Please note station opening hours.
More information about this.
You can use the link here to simulate the shipment (see scan as example).
I wish you a nice sunday.
Kind regards
NicolasK
