Type UIC-I wagons form a set of rail wagons suitable for transporting perishable goods that need to be protected from heat. This UIC type groups together three different types of wagon:
- isothermal wagons, which protect goods from the outside temperature by reducing heat exchange;
- refrigerator wagons (or icebox wagons), which generate cold by means of ice blocks and a ventilation device controlled either by wind turbines located on the roof of the wagon or electrically via a generator driven by an axle on the wagon.
- reefer wagons, which have active refrigeration systems and operate like a refrigerator.
