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The E.421 locomotive was built by Carminati_&_Toselli in 1921, with electrical equipment by Tecnomasio Italiano Brown Boveri (TIBB). The batteries were built by Società Generale Italiana Accumulatori. The batteries were housed in the two bonnets. They weighed 30 tons and supplied electric power at a voltage of 450 V, which operated the four traction motors, one for each axle. The E.421 was used for shunting at the old central station of Milan, particularly in the western area, terminus of the Varese railway, which was electrified with a third rail. It was withdrawn from the service after only two years, in 1923, owing to its onerous maintenance requirements and short operating period - about one hour between charges.
It was stored for a few years, and there was a proposal to convert it to third rail operation, but this was not implemented. The E.421 was scrapped around 1935.
References
Giovanni Cornolò, Locomotive elettriche FS, Parma, Ermanno Albertelli Editore, 1994, pp. 17–20, ISBN88-85909-97-3.
FS class E.421