ÖBB has started to take delivery of its own double deck trains for long distance services. Those are very similar to the Westbahn trains (as they come out of the same factory) and will be used on RJ services on the "Westbahn".
For those not in the known, the "Westbahn", or "Western Railway" is the name for the railway line from Vienna to Innsbruck and beyond. Wien Westbahnhof is named thus because it is the end of that line. There is also an Ostbahn and a Sudbahn, which each also had their own stations until those were replaced with the new Central station. Nordbahnhof however is long gone (But the Nordbahn is not...)
Westbahn will start running trains to Graz and Klagenfurt from March on, using single deck trains however. Double deck trains cannot run on the Semmering Railway yet. For those services they have bought a set of trains, that are the same as the ones SBB uses on Zurich - Milano services. That will mean that they will be running the fastest trains in Austria.
It will be interesting to see if Westbahn ever expands in to Italy or Slovenia.