I have a 10 month old black lab and a 4 year old chocolate lab. They love to chase each other around the house and yard, but rarely get into the train room. The loss of the ac is an exception to get them down there, as well as when there is a tornado warning. Otherwise, I am wary of their tail wagging as it can knock trains off their shelves.
They did do well in sleeping in the train room, as it was nice and cool and they slept on their dog bed.
