Question for experts on the current situation on Vienna public transport

That's a single journey ticket. "Einzelfahrt"

Also, an IC or Railjet train is purchased with OeBB which is different from Wiener Linien which runs the public transportation system in Austria.

Can I ask if there is a reason why you are traveling to Hauptbahnhof rather than taking the S7? Or, can you say where you are headed in Vienna as an IC or Railjet might not make the most sense.

I'm going to the Pension Wild on Lange Gasse. Last time I went I took the S7 to Mitte but I disliked having to make the changes on the U-Bahn with lots of stairs and lifts.

My current plan after looking on Wiener Linien is to get an IC or Railjet to the Hauptbahnhof and then the 13A bus to Jacobiner Strasse. I know it may take longer but it reduces the number of changes. Or I might take the Postbus from the airport to Bellaria Strasse, but that's more expensive.

The airport website says that the OeBB ticket will include a further connection by Wiener Linien.

From the airport machines you can by an ÖBB ticket to the city center, which covers the train to the city and an onward, single ride on Wiener Linien to complete your journey. It's a cooperative ticket between the two systems.

You can also buy an ÖBB ticket to the city boundary and from there your Wiener Linien pass 'kicks in'. That's what those of us who live here and have a Wiener Linien pass do.

An alt route could be the U3 from Wien Mitte to Volkstheater and walk from there. Also a single transfer.

As an aside, you will have lifts/escalators/stairs anywhere you make a transfer to or from rail. If the last time you were here was when Wien Mitte was under construction, that is finished and it is better now. But some up and down is inevitable. All the stations have lifts, though.

According to the official VIenna city map (https://www.wien.gv.at/stadtplan/en/) the 13A bus stop "Piaristengasse" is closest to your hotel.