Railway construction in Austria

No reason to worry. Due to track maintenance on a part of the dual-track route only a single track can be used. To accommodate the traffic the number of trains has been slightly deminished and the schedule of most trains had been adapted to this situation.

If you got to https://www.oebb.at/en/ and enter Innsbruck as starting point, Salzburg as destination, and Schwarzach im Pongau-St.Veit Bahnhof (you need not to type the whole string) as an intermediate point (Via1), you will receive all available options for that journey. Don't forget to uncheck Direct trains only.

To unfold the information about a train click on the downward arrow. If you then select Show All Intermediate Stops you will see the whole journey in every detail, including required train changes. The times given do reflect already the schedule changes required due to the maintenance work.

What this really means is that closer to your travel date you should just go on the www.oebb.at and check what the actual schedule of your trip will bel. The times shown will reflect what will actually run.

Deutsche Bahn is dependend on OBB delivering information, and probalby what they get is not as detailed, hence the different results. But the general rule applies: Always check your schedule on line the day before you travel. Changes are always possible.

Always check your schedule on line the day before you travel. Changes are always possible.

This does not mean that you should not book your tickets in advance.

ÖBB in Austria tries hard to stick to the temporary schedules they had published long before. DB's schedule changes in Germany tend to be more surprising.

Thank you for all the great information.

One additional question: How early do I need to book trains?

One additional question: How early do I need to book trains?

You need to have your ticket in hand before you board the train. So in theory buying your ticket one second before departure is possible. To avoid complications however (you don't want to miss a train because the ticket vending machine decides it needs to do a reboot...) I advise against cutting it that close though.

Most tickets, especially for shorter trips are bought right before travel. Trains are mass transit, used by people to go about their daily business.

However buying your tickets in advance often gives you a nice discount. So if you know you will be travelling then by all means buy in advance. Als for long trips it is a good idea to reserver seats, but that is not possible on all trains.

If the schedule changes between the moment you bought your ticket and your travel date then you ticket is automatically valid for the alternative trains.

... it is a good idea to reserve seats, but that is not possible on all trains.

For all long-distance express trains, bearing RJ/RJX/IC/ICE as a designator, shown in red on https://www.oebb.at/en/, seat reservations are available (and recommended).

Cheap bargain tickets (called Sparschiene) are bound to the train chosen.

Tickets and seat reservations can be purchased separately. Sometimes this is required if you buy the tickets long in advance, but the rolling stock of the train has not been decided on, yet.