My G scale has been outdoors for 15 years now, as well as an around the room loop up near the ceiling of our living room. I started with a nearly ground level line, but dealing with the chores of track up keep and one of our dogs causing issues digging, I rebuilt as a smaller raised line(with a future bigger loop to be added). My track is 100% LGB track and turnouts, trains are LGB and one live steamer(Merlin Loco Works Mayflower). I convered my LGB engines to onboard battery a few years ago and said goodbye to dealing with track cleaning and rail joints that decide to quit working in the middle of a run session. The best way to get started is to just lay some track in the garden and run a train. You will quickly decide what works and what doesnt. My ground level in just had the track floated in ballest like the real railroads are. A spring reballest in places was all that was really needed, along with clearing leaves from the tunnel and plant trimming. The new layout is like a huge planter box, lined with weed barrier plastic(with drain slits everywhere) and back filled with peat moss and mulch. Live plants are planned with a ground cover already doing very well. A rock fountain sits in the middle(and is removed in the winter time). Buildings are lighted with a spare outdoor path light transformer and turn on every night and are lighted for 8 hours or till dawn. Mike the Aspie
Table under construction, all wood is treated
Outer loop in place on temporary supports, I built all track supports out of wood later that day
Here you can see the wood track support and I am starting to position buildings
LGB 2073d with onboard 7.2t Nimh battery power running(5-6 hours of run time on a charge)
And the whole reason I do G scale outdoors, Live Steam! Merlin Locomotive Works Mayflower class live steamer(RC controled)