Transportation - Jiayuguan to Dunhuang

I am planning a trip in October. Due to my schedule the train between JYG and Dunhuang I will not be able to use. I checked the time table already.

Solution: Can you please tell me, when in the late afternoon or evening a bus also sleeping bus if available departs to Dunhuang? How long does this journey take and what are the cost, roughly.

Thank you very much for your support!