A large-area muon imaging system provides a practical solution for non-invasive, wide-coverage subsurface imaging, particularly suited for applications in which access time is very tight, such as (but not limited to) railway tunnel assessment, underground construction monitoring, and geotechnical surveys. Designed to operate in challenging environments, the system enables engineers to detect voids, structural inhomogeneities, and density anomalies in and around existing infrastructure—without the need for drilling or disruption to ongoing operations.