We don’t know yet. We’re expecting everybody that loves Drupal or wants to know more about Drupal. We expect we can comfortably host 200+ people.
By train
Arad railway station is an important connection point for many European rail destinations. International sleeper trains arrive in Arad from Venice, Vienna, Budapest, Prague, Bratislava, Belgrade and Sofia.
Train travel is generally slower than bus travel. See CFR for domestic trains and DB Bahn website for international train timetables and fares.