San Francisco's Market Street subway...
Runs off of floppy disks.
And we're not talking those swanky high tech 3.5 inch floppy disks! No no....
Five.
And a quarter inch.
Floppy.
Disks.
https://sfstandard.com/transportation/sfs-market-street-subway-runs-on-reagan-era-floppy-disks/