The E.333, nicknamed “Signorina”, was a passenger locomotive for use on the Upper-Italian three-phase network. It was designed after plans by Kálmán Kandó and based on the E.552 freight locomotive, but had a similar wheel arrangement to the E.330 express locomotive. Compared to the E.330, it had a lower maximum speed of only 75 instead of 100 km/h, but a much higher pulling power.
Power was transmitted to the central axle over triangular frames. The four continuous speeds were 25, 37.5, 50 and 75 km/h. The carrying axles were connected to the adjacent driving axle by Zara bogies. These were also used to switch the adhesive weight between 45 and 51 tonnes. Their service life ended in 1968.