Objectives Railway infrastructure is diverse in type, large in data volume, and complex in structure. Simplifing its building information modeling (BIM) models is crucial for efficient data processing. However, existing simplifing algorithms face issues such as poor retention of geometric features and significant loss of detailed information.

Methods We propose a simplifing method for railway infrastructure BIM that explicitly accounts for geometric detail features. First, we identify the specific simplifing challenges associated with track, roadbed, tunnel, and bridge models. Second, based on the unique geometric characteristics of railway infrastructure, establish a set of optimization rules including boundary preservation, angle control, and neighborhood area metrics. Specifically, the boundary preservation factor maintains model contours and prevents the formation of voids. The angle error control factor prevents the loss of triangular faces caused by excessive rotation during edge collapse. The neighborhood triangular average area factor helps retain local fine-grained details. Finally, customized simplification strategies are designed for different infrastructure types, and the method's effectiveness is evaluated using five distinct criteria.

Results Comparative analysis of three algorithms shows that our proposed method simplifies the railway infrastructure model more effectively. The method retains more geometric detail features, effectively reduces the geometric error of the simplified model, and provides high-quality visual effects. Furthermore, the test results of the simplification factors demonstrate that the boundary preservation, angular error control, and average area of neighboring triangles introduced in this paper effectively reduce model voids and maximize the retention of model contours, surface features, and local details.

Conclusions The proposed method effectively simplifies the model and is well-suited for simplifing railway infrastructure models.