The conventional ballast track needs to be improved and replaced due to the rapid degradation of the track. While operating the conventional line, the track structure needs to be rapidly improved and constructed in a narrow restricted tunnel space during railway blockade time. Therefore, the precast slab track of discrete panel supporting rapid construction was developed, and analysis and performance tests were conducted. In this study, vehicle track interaction analysis was performed to evaluate the behavior that may occur in the transition of the ballast track and the slab track in the field and to evaluate the safety of the structure during the train operation. In addition, to verify the performance of the prefabricated slab under the load of the train and its applicability to the actual operating line, a load test was performed on the assembly test body consisting of precast panels, rails, and panel-discretely supporting elastic rubber. The results of the test indicated that the rails and panels of the assembled test body satisfied the required performance test and secured structural safety.