## 5 Verification of the Proposed Methodology through the Railway Track Modeling  
A railway track information model was created by integrating AMTs and BATs based on the alignments of the actual railway facilities, and a test was conducted pertaining to the generation of an extended IFC-based model. The target for verification was an actual construction site in Osong-gun, Chungcheongbuk-do, South Korea, where a railway test line was being constructed by KR. The line had a total alignment length of 12.989 km; however, a 2-km section was selected as the target for verification because it contained straight lines, transition curves, and circular curves. Cubic parabolas were applied to the transition curves, and the cant was calculated based on a design speed of 250-km/h. Figure 8 presents the process conducted during the case study of the proposed methodology. Autodesk Civil 3D was used as the AMT, and Revit was used as the BMT. Figure 7: Extended IFC-based information modeling processes for alignment-based structures. Panels (**a**–**c**) illustrate different processes. API: application programming interface; IPF: IFC physical files; ST: STEP Tools; UI: user interface. Autodesk Civil 3D [38] was used as the AMT for the creation of the railway alignment, rails, and ballast. The surface model of the terrain was created using Civil 3D based on a digital map of the area, and the railway alignment was conducted by referring to the design documents. 2D cross-sections were created for modeling rails and ballasts and 3D shapes were generated by sweeping them along the alignment. The \"property data\" function of Civil 3D was used to manage the identifier and cross-section information, which are not included in the basic functions of Civil 3D. Autodesk Revit [39] was used as the BAT for the creation of discontinuous structures. An object library was created in advance to apply the sleeper objects repeatedly and continuously. The \"property sets\" function of Revit was used to manage the identifier and cant information, which are not included in the basic functions of the software. Dynamo Studio is a tool that provides a visual programming environment that can derive results by creating diagrams that include utilization parameters rather than text. Moreover, because it can access the API of Revit, the operation, restriction, and modification of parameters can be easily performed. In this study, Autodesk Dynamo Studio was used to (a) retrieve data from Civil 3D, (b) process these data by applying the algorithm proposed in Section 3, and (c) reflect the processed data in Revit [32]. Figure 9 depicts the algorithm implemented in Dynamo Studio for the shape representation of discontinuous structures. Figure 8: Process for followed for case study conducted at the: Railway in Osong-gun, located in South Korea. Figure 9: Algorithm for shape representation of discontinuous objects in Autodesk Dynamo Studio. Figure 10 depicts the model that integrates the ballast and rail models. The sleeper model included in the integrated model was created using the method presented in Section 3.2. An alignment model was created for the 2-km section by referring to the design drawings. An assembly was created for the shapes of continuous structures, and continuous structures were created by placing the assembly according to the alignment model. The generated alignment was discretized at 1-m intervals to link the Revit with the alignment information and converted into 2001 3D point-data. The alignment was regenerated in Revit based on the point-data, and 3400 sleeper locations were created through Dynamo Studio using the methodology described in Section 3.2. As the sleeper objects were placed in the same shape, a pre-prepared shape library was used. The cant-inclusive rotation parameters of sleepers were calculated using location points of the sleepers and alignment information.