class e.424, having dc type motors like all the italian locomotives of the time, is a rheostatic-type locomotive; on start, a rheostat is connected in series to the motors and is gradually excluded as speed builds up allowing more current to flow to the motors; unlike other rheostatic locomotives of that time, this is not achieved via the characteristic lever ("maniglione"), but through an automatic system, called "avviatore automatico", derived from contemporary first-generation ale 790/880/883 emus.