Sorry, I can't give the exact answer of 100%. According to my understanding, it seems that you are looking for a route that doesn't need to buy more tickets during your trip. First, we need to know the train route between the two cities, and then we can suggest the best route. From Lanzhou to Siping, you can choose the following two routes: 1. Take the train from Lanzhou to Shenyang Station, and then transfer to Siping. This may require buying two tickets, one from Lanzhou to Shenyang and one from Shenyang to Siping. 2. Take the train from Lanzhou to Shijiazhuang Station, and then transfer to Siping. This method may require buying two or more tickets, depending on your stay in Shijiazhuang and the available trains and connections. It is suggested that you check the relevant train schedules, fares and transfer information in advance so as to make the best choice.