Hilldiggers

In Neal Asher's Hilldiggers, during a war between two planets in the same solar system - each occupied by adapted humans - what is thought to be a cosmic superstring is discovered. After being cut, this object collapses into four cylindrical pieces, each about the size of a tube train. Each is densely packed with either alien technology or some kind of life.

They are placed for safety in three ozark cylinders of a massively secure space station. There a female research scientist subsequently falls pregnant and gives birth to quads. Then she commits suicide - but why?

By the end of the war, one of the contesting planets has been devastated by the Hilldiggers - giant space dreadnoughts employing weapons capable of creating mountain ranges. The quads have meanwhile grown up and are assuming positions of power in the postwar society. One of them will eventually gain control of the awesome Hilldiggers....