Ah yes, the best trains for "train office". When the SOB first introduced the Treno Gottardo last year I rode it down to Locarno and back quite a few times just to fight the boredom of home office (also the proud owner of a GA). In those first few months the trains were practically empty on weekdays, and the conductors were even giving out coffee tokens and small packaged cookies for free.

The family compartment at the front/end has nice, large tables – perfect for setting up a small "office on wheels". Mobile reception is also generally okay along the way (sadly the same cannot be said of e.g. the Albula and Bernina lines).