The FS Class E.421 locomotive of the Italian State Railways (FS) was a battery electric locomotive, built as a single unit (E.421.1) and used for shunting at the old Milan Central railway station. It was the only battery electric locomotive locomotive to be registered in the FS fleet.
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 It was withdrawn from the service after only two years, in 1923, owing to its onerous maintenance requirements and short operating period - about one hour between charges.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.