There's no doubt the humidity and high temps in the garage would create some unintended consequences with the wood used on the table, especially with track applied. It's possible the humidity would effect the operation of the engines at some point.
The expansion and contraction of the wood products used on the table will move the track back and forth to unacceptable levels. Working in the summer heat of a garage would be unbearable, and unhealthy as mentioned above. It seems that insulation and AC are the keys to a good operating layout and the most important thing, your enjoyment and health!
