## 1 Introduction
Currently, the application of WRF is limited to the study of drifting snow on the Keta Railway, and there is a need to extend this research to include the study of drifting snow on the southwest railway, which holds significant importance. Regarding the railway in Southwest China, [PERSON] et al. [27] studied the distribution characteristics of extreme summer precipitation and the variation mechanism of total precipitation of the railway using daily rainfall observations and ERA5 reanalysis data in summer. The results showed that the extreme summer precipitation in these areas accounted for 30% of the total summer precipitation, and the extreme precipitation in the central and western regions was lower than that in the east, but with higher precipitation frequency. Due to the scarcity of observational data, some scholars use satellite data to study the temperature and precipitation changes in the region where the railway is located [28; 29]. The WRF model can provide a more detailed spatiotemporal distribution of meteorological information. [PERSON] et al. [30] evaluated the WRF model by examining the interannual variation, spatial structure, and 33-year time variation trend of surface temperature and precipitation. They concluded that the WRF model is capable of accurately analyzing significant weather phenomena on the Qinghai-Tibet Plateau. [PERSON] et al. [31], [PERSON] et al. [32], and [PERSON] et al. [33] have all verified the feasibility of using the WRF model to simulate precipitation in a complex topography area, and many scholars have used the WRF model to calculate southwest China [34; 35; 36]. Therefore, the above studies have demonstrated that applying the WRF model to the southwest region has credibility and can partially compensate for the lack of meteorological data. Existing studies on Southwest China based on the WRF model mainly focus on climate, but there are few applications in terms of engineering in Southwest China. Due to the complex terrain and wide elevation difference in Southwest China, it is very difficult to conduct an engineering field investigation. Therefore, the application of the WRF model to combine meteorology and engineering can produce a large achievement with a low cost. In order to provide an example for the study of the susceptibility of drifting snow in areas lacking measured meteorological information, this paper takes the railway section from Ya'an to Qambo in Southwest China as an object and studies its drifting snow susceptibility based on the WRF results. This research method can provide reference for places with the same terrain and lack of meteorological data and render guidance for railway drifting snow protection in southwest China. The structure of the remainder of this present study is as follows: Section 2 describes the geographical environment of a region which southwest railway passes through, the configuration of the WRF model, and the verification of the simulation results. Section 3 discusses the calculated results of temperature, precipitation, wind speed, wind direction, and the susceptibility of drifting snow on the railway. The conclusion of this study is finally summarized in Section 4.