Krems an der Donau to Vienna train with ÖBB | InterCity

The ÖBB REX is a regional express train operated by the Austrian Federal Railways (ÖBB). It is one of the most popular train services in Austria, connecting major cities and towns across the country. They are semi fast regional trains which call at fewer stations than regular regional trains. There are different ÖBB REX train types like Cityjet, Talent, Desiro and City Shuttle all offering 2nd class tickets only. Some popular ÖBB REX routes include Salzburg to Worgl, Innsbruck to Kufstein and Graz to Seltzhal.

ÖBB Intercity is a domestic high-speed rail service operated by the Austrian Federal Railways (ÖBB) in Austria. They are addition to the Eurocity and the Railjet for long-distance travels and also include first class cars, the trains are air-conditioned, hve power sockets a minibar service and are comfortable. ÖBB Intercity trains mostly run on the inner alpine lines to cities like Graz, Linz and Salzburg and Inssbruck.

ÖBB S-Bahn, short for \Schnellbahn\" (rapid railway), is a suburban commuter rail network primarily serving metropolitan regions in Austria, operated by the Austrian Federal Railways (ÖBB). It functions as a hybrid urban-suburban system, with some larger S-Bahn networks offering services similar to rapid transit. The Vienna S-Bahn, a key part of the network, has been in operation since 1962 and connects Vienna's surrounding areas with the city. It is integrated with the national railway system, sharing tracks with regional and other rail traffic. ÖBB S-Bahn utilizes various train types, including the ÖBB Cityjet, Talent, Desiro, and bi-level push-pull trains. Tickets can be purchased online, via the ÖBB App, at ticket machines, or at ÖBB Travel Centres, with earlier online bookings often offering better prices."

ÖBB Regionalzug (R) is a train category of the Austrian Federal Railways (ÖBB) that replaced the Personenzug in Austria in 1982. Regionalzug services primarily operate in various Austrian states like Styria, Upper Austria, Lower Austria, and Vorarlberg, and on specific sections of other lines. These trains serve slightly longer connections that are too far from urban centers for S-Bahn operations. In Vienna, regional trains from the surrounding areas are integrated into the inner-city transport network. ÖBB Regionalzug services exclusively offer second class. The fleet includes modern trains such as the ÖBB Cityjet, Talent, and Desiro, as well as bi-level push-pull trains and Cityshuttle push-pull trains.