New defective Lionel remote switch?

First of all, see if the problem switch is throwing the points (the movable rails) all the way over in both directions (straight through and diverging) when you put power to it. If the points only move halfway or leave any kind of gap, that could be causing your derailments. You may not have enough power to properly throw the switch (like you mentioned), or there may be a bind in the mechanism. Try throwing the switch manually and see if there's a glitch in the mechanism.

I checked to see if the throw points are switching fully, and they are.  I tried manually switching it and the train still derails.  The other switch seems fine, but with his trouble makes in one direction the train goes over it roughly, the opposite direction and it derails.  I tried checking it with a straight edge and the tops of the rails seems even through out.  Even screwing it down to the table didn't make a difference.  There's something about this switch....maybe it's time to return it to the shop.

I think that would be the best thing. No sense in wasting more time with it.

I figured I'd post an update to my switch problem.  I ended up taking that piece back to my Train Store yesterday.  They swapped it no questions asked.  The new switch works much better!  While there (I had my son with me) I splurged a bit.  MY son did great on his report card recently, and badly needed an additional transformer for his track so we picked up a Lionel Santa Fe Chief RTR set.  What a nice train!  We have the transformer to use on his layout, a really nice diesel train with coaches, and an extra oval to use for under the Christmas tree next year.  Sometimes those sets are a great value.  My son loves all the sounds of that Santa Fe...and wow is it fast, and pretty!  A quick note for anyone nearby my area (Southern NH).  The shop I've been going to is "Trains on Tracks" in Amherst NH.  It's a really nice store, with a fantastic group of guys...and incredible prices.  I'm very glad I found the store.  Well, it looks like my son has made me a train nut!! hahaha.  We're having a great time.  Thanks again everyone.

Good for you and your kid man. It's great to see a young boy take an interest in trains!Have fun.