I hunt along side a railroad track where there are old used telephone polls that are only about 15' high... if I were to setup a tree stand on the telephone poll at the height of 10' to where I am looking directly across the trail and I am prolyl only 15 to 20 yards away...is that a good setup or do I need to be higher??

higher would be alot better

I would want some cover around me. A telephone pole offers no cover whatsoever so I'd want to be much higher, maybe 25 feet or so.

You can get away with 10 feet if background cover is there to break up your outline. On a telephone pole I think you'd stick out like a sore thumb. But if the deer aren't spooky you might get away with it.

Why does it ring a bell in my head that telephone poles are a No-no for using as stand sites?..........safety, legaility? Heck I can't remember.[&o]

If there isn't an issue with actually using the poles, 10ft is OK as long as you have sufficient back cover, and proper wind direction.......and some unpressured deer. You definitely don't want to look like a loli-pop.
There's places I've hunted where if you tried to hunt 10ft up in an exposed telephone pole all you'd be able to hear are the deer laughing well before you didn't see them.

Also try to chose a specific stand where the deer's primary travel route doesn't angle toward your stand at all. Don't give em' an excuse to simply raise their heads....and laugh.[8D]

I think it would be better if you got a little higher, but if you can't it might work.

Matt, I was thinking the same thing. I know I read that somewhere.

To answer your question: yes, 10 feet is fine if you have good background cover.

I also think that the legality depends on the state, county and property it sits on. We have poles also that run on the property. It's legal to use them because they are considered part of the property but there's a serious safety issue to be addressed depending on if it's a active pole or deemed no longer safe for use. Make sure it's legal and safe1st.JMO

Depends on the set-up. I've hunted no-more than 8' off the ground to be in the right spot before. You simply must consider wind beyond anything else!

For starters you'll be trespassing , telephone poles are always on private property .

Guilty, Ive hunted telephone poles. You are sitting out like a sore thumb. Dress like a transformer. You need to be in a place where they are moving through without stopping. You need to be able to hit a walking target.