T116 is overall not bad. But it stops in more cities than Z along the way. I am pretty sure that the YZ ( hard seat) cars will get packed over night during the time you travel. If you get a window seat, good for you! You may get a bit of sleep over night. If you you get a aisel or middle seat, brace yourself.

Also drinking beer is not a good idea cause you may have to fight your way to the toilet more often. And you may find people settling down there all the time too..

If you are in the middle of the train just go to the office and try to get an upgrade. Go there as early as possible once you get on the train and don't leave until you've given the final word. Some people pay 50 Yuan to get a seat in the dinning car. But since you've gotten a seat already it may not apply to you.^

Good luck!