The ACs in the train have a rough time keeping up in the summers. Especially on the express and and Epcot trains. Every time that train arrives in the station, it opens the doors on both sides for a few minutes. Letting that nice breeze blow out all of the cold air. By the time the air temperature build up to a cold level again, you're arriving at the next station and the doors are opening again. It's like sitting in the drive through with all your windows down and the act on max. Your not going to feel that at nor will the car retain any cold with the windows down.