In this story a huge tripod alien ship has invaded and is perched over the central US. The aliens have wiped out all tech and sent most human population back to the Stone Age. Still, there are pockets of resistance remaining, and the humans, with still a few remaining atomic bombs, are desperate to topple the spacecraft, so that they can defeat the aliens with sheer numbers. They invent a silent friction climber and send a guy up to climb one of the legs with an atomic bomb to try to bring the massive ship down. I read this story sometime in the 80s, unknown anthology.
The ship has been there for many years and the aliens have never emerged or done anything. The team attacking the ship are able to pick up a sound inside which they eventually identify as an endless screaming, and realise that the aliens have become insane, and so will never be able to carry out whatever they originally intended to do.