Track transportation system is the dominant transportation system for many construction drifts of long tunnels. In the construction of the parallel drift of Xiushan tunnel on YuxiMengzi railway, the track transportation system is converted into trackless transportation system inside the tunnel by using the cross tunnel connecting the main tunnel and the parallel drift. The conversion from the track transportation system into the trackless transportation system is presented in detail in the paper. A comparison is made between the track transportation system and the trackless transportation system in terms of safety, construction speed and economic benefit and conclusion is drawn that the track transportation system plus trackless transportation system adopted for the parallel drift has obvious superiority to the simple track transportation system. This paper can provide reference for similar projects in the future.