The arteries are clogging in the mainframe
There's too much information in the pipes
These lines seem deliberately obscure; mainframes don’t have arteries, and pipes don’t generally have information (what they tend to have is water, or waste). There is an implication, however, that evidence was flushed down the pipes, probably in a hurry, and that the black-booted, hazard-suited men are going to be able to glean some information from the sewer drain.
To help improve the meaning of these lyrics, visit "Your Belgian Things" by The Mountain Goats Lyrics and leave a comment on the lyrics box