at todays g scale train show i got a bachman large scale pennsylvania elec set can i use this outside and if so how to use best
No, because Bachmann track is for indoor use only, you would need to buy track appropriate for outdoor use. I think stainless steel track would work good.
gww-
You can use your Bachmann track outdoors but don't leave it there. It isn't stable under the UV in sunlight and will fail very quickly if it isn't put away. Because of this, few people use Bachman track outside. There are several manufacturers of outside safe track. The material in your rails can make quite a bit of difference, depending on how you'll control and power your trains. For example, if you'll be powering and controlling your trains through the rails you'll want something which doesn't need constant cleaning to work well, like stainless or aluminum. If you use batteries or live steam and radio control the rail metal doesn't matter much except as regards appearance and cost. Good luck with your new railroad.
-- D