what is the best train out of Vienna to get a look at the countryside in the winter months? I feel a train ride to be a wonderful way to see the countryside of another country.
Trains from Vienna toward Semmering, Kalgenfurt, and Villach, and branching west from that line toward Kitzbuhel, Innsbruck, and the Swiss border all marked as "scenic" on my rail map, mostly for mountain scenery. The faster line running via the Danube valley and Linz to Salzburg doesn't get the same rating, and mostly does not follow the river, but is a route with worthwhile destinations such as Melk, Krems, and Mauthhausen Memorial.
I would suggest to ride the "Mariazellerbahn" from St. Pölten to Mariazell. Not only the historic track is scenic, Mariazell itself is worthwile visiting, a pilgrimage town with an outstanding basilica.
https://www.mariazellerbahn.at/en
https://en.wikipedia.org/wiki/Mariazell
Express trains run every half an hour from Vienna to St. Pölten (25 minutes ride).
I always enjoy the train ride from Vienna to Graz, and Graz is a very nice destination to stay for a day or two.
I second the Marienzellerbahn from St Poelten to Marienzell and the ride from Vienna to Semmering and you can get off at the next stop which has a Museum about the building of the Semmering railway with lots of trains and exhibits with its original turntable.
Mike
thank you all for our input.