The kkStB 30 were a class of 2-6-2T locomotives designed by Karl Gölsdorf for use of the Vienna Stadtbahn of the Imperial Royal Austrian State Railways (kaiserlich-königliche österreichische Staatsbahnen).

The second prototype was given a modified arrangement of wheels and valve gear that better met the requirements for reversing and was retained for series production.

Sixty-two locomotives belonged to the Commission for Transport Systems in Vienna, one by the Niederlindewiese–Barzdorf local railway in Austrian Silesia, the remainder by the kkStB.

The Stadtbahn's locomotives ran from the start, based on the Berlin model, with destination signs on the smokebox door or on the rear bunker, as is a matter of course today.

A discharge pipe led from the low-pressure cylinder to a special part of the left water tank, in which the steam was condensed.

A ventilation pipe passed over the roof of the driver's cab was supposed to divert the steam remaining in the condensation chamber.