Vellum in printers, millions of cards on the eleventh floor ... were they just relentlessly dense?
First question: what saved them from a building collapse? Second question: what kind of printer did they use for the vellum? Laser would involve heat, and that would be very weird, but ink is equally strange.
Question one: the punch cards were eventually transferred to tape, and later disks. The system was a 1401 assembler port of a hard-wired IBM 407 accounting machine app. In turn the 1401 emulator was run under VM370 as a virtual machine.
Actually, the operators loved it, because each one could have his "own" 1401 with card reader, printer, punch, and virtual console. The original app dated from the mid-1950s.
In truth, the City-County building was condemned as unsafe from the day it opened in 1949. It was built by the mayor's brother. It took a year of reinforcement before anybody was allowed above the first floor. With 18 million punch cards on the 11th floor, you could feel the floor wobble whenever someone walked by. Our office was on the opposite side of the building, and I never went near the assessor's office again. It was only by some miracle that half the building didn't collapse. Elimination of the punch cards saved it.
Second question: the forms were printed on a IBM 1403N1 chain printer. It was probably the fastest, neatest, and noisiest mechanical printer ever made. This was in pre-laser days.