Use ÖBB's [url=http://fahrplan.oebb.at/bin/query.exe/en?]SCOTTY[/url] to look up train information
From the west take the regional train (Regionalzug, denoted by big R) from St. Pölten (usually every 30-50 min. every hour) to Krems.
All other directions regional (express) (Regionalexpress, denoted by a big REX) train from Vienna's Franz-Josefs-Bahnhof, Spittalau (U4, U6) or Heiligenstadt (U4) station which takes about one hour and leaves every hour.
From west: Highway A1 (Westautobahn) to Melk, B3 through Wachau.
From South/East: Highway S33 from St. Pölten or A22/S5 from Vienna
From North: B37 via Zwettl or through the Kamptal/Horn