Xian to Zhangye how long by train cost 2 adults once there who do you recommend for tour group to go.

There are fourteen trains between the two places and the duration is different from 13 to 20 hours. For detail time, you are suggested to search in the Train Section on this website and I am sure you will know it clearly.

I know little about the tour group, because I usually travel out on my own. I am sorry.