We need to know the route. It seems very weird that you couldn’t stand in 1st class.

When seat reservations are required, they are for both 1st and 2nd class passengers.

It was from vienna to hallstatt.  They said eurail first class had to sit in 2nd class or had to pay extra to enter their first class cabin. Something about being a private train which i dont understand. As there were no seats, we had to stand.  Whats the point in purchasing first class then.  Am I going to have the same problem travelling to Innsbruck tomorrow from Hallstatt?

You surely took a Westbahn train (private company) and not a OBB (national company) train. On Westbahn trains Interrail/Eurail passes are indeed only valid in 2nd class (strange rule I agree).

As long as you take OBB trains tomorrow, you’ll have no problem finding seats. On bahn.de (reliable planner) Westbahn trains are marked as WB

Edit : you can make a seat reservation on tickets.oebb.at (no booking fee) if you want. They’re free for 1st class pass users

There’s a reason we ask for specifics as  without knowing which train it’s just speculation.

There are no requirements for reservations or additional charges for 1st class on Austrian day trains except for those operated by Westbahn who only allow interrail including 1st class holders in 2nd class.

All other trains run by the main operator in Austria OBB you can use 1st class but not business class without any charge on a 1st class pass, reservations are not mandatory but obviously if the train is full and you don’t have one you will have to stand or take a later train.

Thankyou so much. It is all so confusing and no humans to ask questions at stations.  Must admit finding it very challenging when the only language I speak is English.