Overnight train Beijing to Xian

Caught the train at Beijing West Station. Waited in a pay lounge for the train to depart. Cabin is 4 berth and we travelled throughout the night. Space/ is very cosy with  4  bags and assorted backpacks. Ate a lot of rubish on the train. Buying food in China can be a bit of a lucky dip as you are not quite sure what you are buying. The other night we managed to buy aluminium foil instead of small ziplock bags.
Have just woken up and train is heading in opposite direction but we are still travelling southwest. So I guess we are going to the correct place.