The NS 3400 was a series of goods steam locomotives of the Dutch Railways (NS), ordered by its predecessor the Hollandsche IJzeren Spoorweg-Maatschappij (HSM).

Due to the merging of the fleet of the HSM and the SS in 1921, the locomotives were delivered with the NS numbers 4101–4120.

In the same year, the locomotives were renumbered in the definitive numbering as series 3401–3420.

During the Second World War, three quarters of the series (3401–3412, 3415, 3419 and 3420) were deported to Germany, of which thirteen returned.

Until 1953, these served mainly in the Rietlanden and for the oil trains from Schoonebeek to Pernis.