# Integration of BIM Tools for the Facility Management of Railway Bridges
## 3 Literature Review
### BIM/Data Automation as an Initial Step Towards a Digital Twin  
With the technological advances of recent years that have given rise to the era of Industry 4.0, there has been a notable change in how the AECO industry manages its projects, moving towards digital transformation at different levels and, in turn, automating facility management activities to improve work efficiency during the operation and maintenance phase [33; 41].  
Before the advent of BIM, most facility management tasks used Autodesk(r) CAD (2024) files for asset management, but there are several problems with using these files for facility management, such as the lack of integrated correlational information in CAD drawings, inefficient coordination between different specialties, and complexity in interoperating with other software [43]. The application of BIM to infrastructures is effective for managing their life cycle, encompassing everything from the design stage to maintenance. In particular, implementing BIM in infrastructure has considerable potential to add value to assetmanagement in the maintenance stage, that is, for facility management [66]. Digital twins, in turn, serve to virtually replicate the asset with parameterized models that evolve over time and remain synchronized with their physical counterpart through data collection instruments [42; 48; 52]. One advantage of this technology is that it allows interaction between physical components, products, or systems (depending on the case) in physical spaces and their corresponding virtual replicas in virtual spaces, integrating multiple physics and scales, and generally using sensors and/or current or historical data, enabling a complex virtual model that is the counterpart of the physical one [67]. Another advantage is that they help monitor anomalies, fatigue, geometric deformations, etc., in the physical twin [68]. Digital twins in facility management are also used for preventive maintenance of assets, improving decision-making, inspection task efficiency, and reducing safety, economic, and social costs [33; 41; 42; 69]. The use of digital twins varies depending on the area where this technology is employed, as there is evidence of their use in the construction and monitoring of wind farms, for regional energy systems integrated into smart cities, for fault detection in buildings, and for supervising and managing construction progress [51; 67; 70; 71; 72].  
Therefore, the technology to be used will be a BIM/data automation as an input for a digital twin that provides the significant advantages over traditional methods mentioned above. This BIM/data automation is considered in the literature as a Digital Shadow, which differs from digital twins by being a model fed by a unidirectional flow with the state of a physical asset, understood as a mere assignment of status data through measurement to a specific asset at a given point in time [52]. Although the greatest advantages come from digital twins, BIM/data automation also offers benefits such as interoperability, collaboration, and communication among stakeholders that BIM itself provides, reduction of information loss, improved data accessibility, reduced time and cost to update monitoring system databases, support in decision-making, among others [33; 40; 41; 43; 44].