Train from Beijing to Datong.

We plan to take an overnight train from Beijing to Datong, we have the following questions :

1. We will be staying in the Great Wall Sheraton Beijing in Chaoyang district. Which train station do we have to board the train?
2. Are the beds in soft sleeper clean? Does the cabin has a private toilet & washroom?
3. We believe the cabin has 4 beds, so we need to purchase 4 tickets if we want to use it for the two of us.
4. Which Datong Station should we choose : Datong or Datong East? We will be staying in Datong center.


Thank you.