Solo traveling 38 hours on a train? Tips and packing advice?

So I’m planning to go to Tibet and for altitude acclimation reasons, I plan to take the train to Lhasa. While I’ve taken the train before, I’ve never done a journey longer than 7 hours or so, so I’m curious if anyone had any tips or advice to make the journey more comfortable.

As of now, my packing list is:

* Basic toiletries
* Entertainment stuff
* Earplugs and facemask
* Travel towel
* Comfortable lounge clothes
* Snacks
* Tea bags and instant coffee
* Thermos

Am I missing anything? Anyone else do this journey? Or a similar journey? Were there any things you took that were ultimately useless? Things you regretted not taking? I already plan to travel on a soft sleeper, which comes with pillows and blankets.

Edit: Thanks for the suggestions! I’m gonna add a few things to the list:

* Disinfectant wipes, baby/wet wipes, and toilet paper
* Trash bags- didn’t even think about this one but it makes total sense
* Wearable pack/fanny pack- smart for keeping the passport, cash, and phone always on myself.
* Power bank- I thought about it before but forgot to write it down for some reason
* Tummy ache medicine– this one I hadn’t even thought of. I have a stomach of steel most of the time but you never know. Better safe than sorry. I’ll add a small first aid kit with bandaids, ibuprofen, extra masks, etc, too now that I think about it.
* Slippers/flip flops– I heard the soft sleepers already provide them but like with the tummy ache medicine, better to be safe than sorry.

Solo traveling 38 hours on a train? Tips and packing advice?