The initial project speed was 160 km/h (99 mph), but later it was reduced to 150 due to stability problems; further, the heavy mass of the locomotive did not allow the use of rheostatic braking.

The different connections of the motors in the various combinations are accomplished by closing various contactors; their set-ups during transitions are handled by a device called "CEM" (Commutatore Escluditore Motori).

On Third series locomotives (official classification), many functions such as the ones of RAE, Avviatore Automatico, CEM, etc., are assumed by an electronic control unit (called Delfina) derived from the ones employed on FS Class E.444.

The rheostat is robust and designed to stand high currents, however it cannot for an excessive period of time, as there is the risk of overheating; the driver has to keep this in mind when driving.

When the temperature is too high (greater than 200 °C or 392 °F), the "VR" (Ventilazione Reostato, Rheostat Fans) light starts to blink on the driver's console to warn him.