SOLVED. Series of SciFi & Fantasy Novels circa 80's-90's. Following atomic war US is divided into two civilizations. There is a militaristic high tech society living underground, and a primitive group with native lifestyle living above ground. [s]

[Ian]

Following atomic war US is divided into two civilizations. There is a militaristic high tech society living underground, and a primitive group with native lifestyle living above ground, these are considered mutants by the subsurface dwellers, who are trained to infiltrate & destroy the native society. There is blatant animosity between the two societies & series follows adventures of one character ordered above ground to infiltrate & disrupt activities of a local tribe. (Spoilers) Later on in series, we discover that all the high tech warriors originate from children abducted from primitive societies. Think there are 7-8 books in series. Any help gratefully appreciated

[Andy Phillips]

This sounds a lot like the Amtrak Wars series of six books. The first is Cloud Warrior. I'm not sure it's quite right though as I don't remember the abducted children.

[Ian]

Andy Phillips wrote: "This sounds a lot like the Amtrak Wars series of six books. The first is Cloud Warrior. I'm not sure it's quite right though as I don't remember the abducted children."
Many Thanks Andy...That is the series of books I was thinking about. If memory serves me, the abducted children refers to the gathering of survivors from decimated communities.

[Andy Phillips]

That's great - glad you found it. I'm sure you're right about the children, I just don't remember that bit. I do remember a lot of stuff about train-like vehicles, Japanese people on boats and a horrible ending to the sixth book that made me regret reading the thousands of pages across all the books!