Vibrator supplies were very common for car radio equipment in tube/valve days. You need to apply some good filtering though to get rid of all the spiky waveforms and harmonics generated by the vibrating contacts.
These days, there are even specialist places selling solid-state replacements for those who like to keep their old radio running in a vintage/classic car.
to transform the 12VDC to 250V
And don't forget that prior to the mid-1950s or thereabouts, most car electrical systems were 6 volts.
