danxia mountain in zhangye

The train from Lanzhou to Zhangye takes about 5 hours, and then another 1 hour from the railway station to the Danxia landform. So you will spend most of your time on the road. If you can catch the early morning train from Lanzhou, you might finish the visit in one day, then you can take an overnight train back to Lanzhou or stay one night in Zhangye and get back to Lanzhou the next day.