Abstract: In order to improve the efficiency of traditional architectural design and management, and reduce engineering construction costs, this paper studied the virtual construction technology of railway engineering units based on BIM (Building Information Modeling). The paper divided railway engineering units into functional units, specialties, work items, components, etc., and simulated to improve and optimize the construction process through key technologies such as document process engine, electronic sand table, and simulation simulation, the construction process of key units to improve and optimize the construction process. The research results can effectively improve the efficiency of actual engineering construction and provide technical support for the comprehensive application of BIM in railway engineering.