Digital Reconstruction and Augmented Reality for Documenting and Interpreting Steam-Engine Heritage: From Newcomen to Watt

Digital reconstruction and augmented reality are increasingly used in industrial heritage, but relatively few studies document the complete and reproducible process from historical data acquisition to the final AR-ready model for public exhibition. This study proposes a transferable workflow for the digital reconstruction and dissemination of historically significant machinery in publicly accessible virtual museums. The methodology was applied to the reconstruction of the steam engines developed by Thomas Newcomen in 1712, together with the improvements subsequently patented by James Watt in 1769. Historical drawings, patents, technical descriptions and dimensional references were analysed to reconstruct the machines as hierarchically organised CAD assemblies. Reconstruction decisions were documented through a traceability matrix distinguishing documented, inferred, reconstructed and simplified elements. The resulting models were validated by checking dimensional consistency, component positioning, mechanical interfaces and functional coherence with the historical sources, while their kinematic behaviour was additionally verified using a motion study. The validated assemblies were subsequently converted and prepared for web-based augmented-reality visualisation. The proposed workflow constitutes a replicable methodology to the reconstruction and interpretation of other historical machines, particularly when surviving physical evidence and technical documentation are incomplete or dispersed. Given the incomplete nature of the surviving historical evidence, the resulting models should be interpreted as technically coherent and traceable reconstructions rather than exact reproductions of the original machines.