After exhaustive searching, I booked a T6 Couchette on the City Night Line for 4 people after hearing from some friends/colleagues that we would likely have the cabin to ourselves. After perusing the internet, I am getting concerned that this may not be the case. T4s were not available and the double sleeper was extremely expensive. Can anyone comment on this particular route, popularity, etc.? Also, how difficult is it to upgrade the tickets once we are at the train station in Italy, obviously provided there is availability.
Thanks!