The railway is one of the main pillars of transportation in any country, and it plays an essential role in the movement of passengers and goods and has significant economic and social effects. Earthquakes, as one of the unpredictable natural hazards, can cause long-term blocking of the rail transport network and financial and human losses. From this point of view, it is imperative to maintain the safety and status of stations, bridges, tunnels, and railway lines as the most vital rail transportation infrastructure. Razavi Khorasan province is one of the provinces prone to earthquakes in Iran. The railway lines of the Khorasan General Directorate of Railways are also of considerable importance in Iran's railway network from the perspective of moving a large number of passengers to Mashhad city and the transit of goods through Sarakhs International Railway Terminal. Therefore, it is necessary to strengthen the infrastructure of the railway network against earthquakes to maintain safety. Considering the economic and operational limitations, evaluating and prioritizing the seismic retrofitting of rail transport infrastructure is necessary, which is regarded as the primary goal of this article. In this study, first, with the help of the expert team and using the fuzzy screening approach, the critical effective criteria in the evaluation and prioritization of seismic retrofitting of infrastructures were identified. The most important indicators for evaluating seismicity intensity, distance from the fault, type of use (passenger and cargo), and the current state of infrastructure resistance were selected. Then, the expert team evaluated the current state of each infrastructure (station, bridges, tunnels, blocks) using fuzzy logic. In the following, according to the evaluation of the expert team and the screened indicators and using the TOPSIS fuzzy method, the most critical priorities for retrofitting were evaluated and identified. For this purpose, the geographical information on seismicity intensity and the location of faults in Razavi Khorasan Province was matched to the railway network of the Khorasan General Directorate of Railways. The results of this study show that the Torbat-Abumuslem and Abumuslem-Kashmar blocks with proximity coefficients of 0.25 and 0.28, respectively, have the highest priority for seismic retrofitting. The need for seismic retrofitting of all three tunnels in the Khorasan region with a proximity coefficient of 0.544 is assessed as medium. Among the bridges studied, Attar Bridge and Shahid-Motahari Bridge with proximity coefficients of 0.322 and 0.447, respectively, and among the stations studied, Neyshabur and Shahid-Motahari stations, both with a proximity coefficient of 0.322, require more attention in seismic retrofitting. The results obtained show that the railway axis from Motahari station to Mashhad and from Mashhad to Niqhab, especially the blocks between Fariman and Kashmar, Attar and Motahari bridges, and Neyshabur and Motahari stations, have a higher priority for seismic retrofitting.