Due to heavy rains in the Alps last week (and also, apparently, planned engineering work) the rail links through the Alps are seriously disrupted. This affects the Chambéry (FR) to Milano (IT) route, as well as (critically !) the Milano to Baveno connection. On the other hand, the rail line from Domodossola (and Switzerland) to Baveno seems Ok.
This is particularly going to affect those of you coming from Milano airport. If you find yourself in this unhappy situation, please investigate asap your travel options (we would suggest the bus company Alibus, https://www.safprenotazioni.com/SafAlibus2000/index.xhtm ).
If you cannot find a solution, please let us know before the end of Tuesday 5th (18.00 Europe time) and we will see what we can organize, probably at a cost.
The Massif Central field trip, on the other hand, has already organized alternative travel plans (through Geneva and Brig, meaning an early start on Saturday morning).
Also note that the Baveno-Milano line should reopen on the 11th of September, so there should be no difficulty for your return to Milano.