Yes, an overnight train is a good option on this route, although you might find a cheap flight. There’s a direct overnight train now on this route and there is probably one year around. Check the schedules after mid September. I think the German rail website is the easiest to use: http://reiseauskunft… I would buy the ticket as far in advance as possible. I don’t see any special fares for the direct overnight train on the German site, so it must by an Austrian train. The Austrian rail company website, http://www.oebb.at/e… shows specials as low as 49 euros.

Use www. whichbudget.com to see which low fare airlines fly which route and check our “cheap flights” forum for more links, search engines and tips. You might find a flight that’s significantly cheaper than regular fare on an overnight train.