The precise surveying of railway infrastructure under live operating conditions represents a significant challenge. Strict safety requirements, limited accessibility, and operational constraints considerably restrict conventional measurement methods. The use of drone-based laser scanning provides an innovative and practical solution. UAV-based LiDAR data acquisition from outside hazardous areas significantly enhances personnel safety while enabling efficient capture of large track sections within short timeframes. High absolute accuracies are achieved through the integration of kinematic UAV scan data with terrestrial laser scans. Georeferencing is performed via track survey control points, which are automatically detected and incorporated within the terrestrial datasets, ensuring a robust and consistent overall geometry. The presented method combines safety, efficiency, and precision, offering substantial benefits for end users in the digital acquisition, analysis, and planning of railway infrastructure - even under real operating conditions.