Cold wagons... not as such. We do however have wagons used by the Butchers Clan and the Cooks Clan as sort of cool storage for meats, fruits, veggies, perishables. Flaps and smoke holes opened during cool nights, cool to cold water used to help lower temps when available, that sort of thing.
It would not be a major production... just somewhere other than out in the sun to keep perishables from going bad before their use. Just cool and damp as much as possible. No real special wagons or anything. Lots of cloth soaked in cool water and wrapped or covered items. That sort of thing.
Remember though... as Tuchuks in general did not eat, in general, things that came from the dirt, these wagons would be very limited. They did not eat such things likely because, to a great extent, the inability to keep these things from going bad and their migration practices.
