Unfortunately, I haven't found the relevant information yet. I suggest you call the bus station directly, which is more reliable:

Major Long-distance Bus Stations and Consultation Telephone Numbers in Lanzhou

Station name address telephone station name address telephone

Huanglou, Pingliang Road, 841841KLOC-0/Xiaoxihu Bell Tower, and 2663285 West Bus Station.

Pingliang Road of Coach Station1318410573 Dashaping of North Bus Station 128 8369975

Tianshui Road Bus Station Tianshui Road 13486 15637 Long-distance Xigu Bus Station West of Qingshui Bridge 73 19587

Pingliang Road 147 Bus Station 8720887 Wulipu Lan Xin Market 849930 1

8664273

The following is the coach information of Lanzhou:/Changtu/Changtu/Gansu/Lanzhou.htm.