I learned how to operate a fire truck/pumper by driving a 1959 Seagrave open-cab. It had drum brakes that were good fro one hard stop from 60 mph, and then you had to let 'em cool-down before using them hard again. Not really what you want for a fire-truck! It also had a non-synchro gearbox, four speeds, and you needed them all. Tops was about 65 mph.
It had a 1000 GPM centrifugal pump. It also had "The Light from Mars," a rotating side-to-side red emergency light like a hood ornament. Below that was a mechanical siren, it looked-like a squirrel cage inside a big chrome bezel, and it wound-up, and it wound-down. So, the pitch began low, and as the pitch increased, so-did the volume, and vice versa, you had to manually allow it to cycle, it wasn't automatic like the Federal audible warning devices of today, the ones w/all the different patterns.
If you ignored the pitch of the siren (admittedly hard to do, as that was its purpose to get your attention, "here-comes the fire truck!") the sound of the cage spooling up and back-down was just like the noise that supercharger makes. Ah, memories...
FYI, an interesting factoid, the Seagraves Fire Equipment Company, now a WI company, bought the rights to their straight-eight engine design from an automobile company formerly-based in western NY, Buffalo. Anyone know who that might be, without Googling it? C'mon you guys in Elma and Fairport, Buffalo and Tonawanda! Who'sThe Gearhead?:ummm: