Hi, I'm looking to travel from Germany (Cologne to be precise) to Vienna this summer for 2 adults (possibly 4) and 2 kids on the NightJet sleeper service. It's hard to see on the Rail Europe website how this would work as looks like tickets don't go on sale until 90 days beforehand but I just wondered if anyone else had done this and how it worked/how they booked it? Is it included in an Interrail pass? I know seat61.com has info on it but wondered if anyone here had first-hand experience of it?