I have four conventional locos, two with railsounds, one with trainsounds, and leave them boxed in garage for years with no problem. Temps rarely below 10 degF
My layout is in a separate building; I live on the Gulf Coast, so summer is the dominant
season, not winter. A small 110V A/C unit will get my shop (12X24) nicely cooled
(the big live oak shading it doesn't hurt, either), but in the winter my space heater (ceramic) can take a while. The shop is well-insulated - except for the floors (it is built off the ground on piers, with a crawlspace). This helps the A/C, but is chilly on the feet in the winter. And we DO get winter - it was 24 overnight 2 days ago in the northern end of the county. It's 41 right now (10:00 PM).
My point is, go with the Mitsubishi heat and A/C units, and, more importantly, make your
garage as house-like as possible. Jury-rigged anything(s) eat into the enjoyment of
the hobby, sometimes fatally. Spend some time and money to be comfortable.
Also, I have all kinds of electronic locos, TMCC system, DCS Remote Commander and
so forth in there, some since the early 90's, and the cold and much-vaunted "Gulf Coast
Humidity" (kinda overrated) have never hurt a thing. Of course, I don't get snow and
ice and the frigid world that goes along with that.
Now, I really should go heed my own "be comfortable" advice...
One thing I founf, sunlight shining thru windows can cause repetitive rapid changes in temperature, in cold weather condensation is more likely to form on metal surfaces causing some rusting. But cold itself shouldn't really affect anything.
