European trains normally only have 2nd and 1st class coaches. There are a few exceptions.

If the train company running the train doesn't offer business class, then there is no business class.

I am sure that just booking a seat in a higher class on a seat only option would result in the inspector being unimpressed.

Imagine having a second class ticket (or interrail pass) and sitting in first class, and arguing that by reserving a seat in 1st class you have found a new valid way to travel for only a few euro. 

In the UK we can get free reservations by simply declaring we have a ticket - why then would anybody pay first class when they could pay second class, get a separate reservation for 1st class and claim they have an upgrade.

We actually travelled yesterday in the UK and changed our plans to an earlier train. we got new reservations. The ticket clerk merely asked if we had a ticket but didn’t check my assertion.

The reservation clearly said it was only valid with a matching 1st Class ticket.

Hi Amy22,

it’s absolutely no problem to book it that way. ÖBB allows the business class upgrade to your 1st class ticket for 15 € per person (in Austria you get a free drink of your choice, too). Using the seat only option it’s also possible to choose your exact seat(s) from a plan by clicking “RESERVATION DETAILS” and then “Go to seat selection” on the next page.

Hint: You’ll also have lounge access in Budapest Keleti doing it that way (the train departs normally exactly where the lounge is).  

Kind regards, Hektor