This hefty 2-6-2 was built as part of Tešlov's new standard design concept, which had begun with the 323D of 1933. A semi-fast passenger locomotive was needed for the more heavily-laid routes over the southern highlands, the line from Kropčahne to Forihv being particularly arduous. Tešlov used a shortened version of the 1a boiler from the 344D and 433D, but the grate area of 5.1 square metres was retained, giving the locomotives ample capacity for sustained hard steaming. The adoption once again of a 3-cylinder simple layout, instead of the compound arrangement of the 344D, was a clear indication that Tešlov had turned his back on compounding. Henschel, of Kassel, supplied forty engines in all in late 1937 and early 1938. Supplanted after the Second World War by more modern designs, in particular Rodnivacek's 4-8-0s, the 333As disappeared relatively early, the last ones being scrapped by 1963.

The 1938 rebuilding programme also called for new tapered boilers for the 333As. The design was drawn up accordingly, but no engines actually carried the new type of boiler.

Text and graphics © Norman Clubb 2012