Dalian to Beijing on the night train

There is a sign on the toilet that says "no occupation while stabilizing".

I'm not totally sure what this means, but I assume that at least in my instance, if you have been pigging out on Dalian seafood at an all you can eat sea food buffet, and as a result feel you need some stabilisation, do not spend time doing it in the toilet.

Interrpreting more widely, it also might mean, don't do your business while the train is at the station.

As the sleeping cars were full, and only seated and standing places were still available, the remaining good spots filled up fast