On Sunday 11th December 2016 the timetable for late 2016 and 2017 commences. The timetables have not been confirmed as yet so keep checking back as I will update as and when they are published.
If you want to travel between Sapa or the Vietnam–China border and the Vietnamese capital, Hanoi, taking the Lào Cai–Hanoi train is the best option. On my blog, I show what the journey is like and how you can book tickets.