EVALUATION OF RAILWAY TRACK DEGRADATION RATE BASED ON TQI TRENDS: A CASE STUDY OF THE KOLASIN–PODGORICA SECTION

Understanding the rate of track degradation is essential for effective railway infrastructure management, particularly in mountainous and geotechnically unstable regions. This paper presents a comprehensive analysis of the track geometry degradation on the Kolašin–Podgorica railway section in Montenegro, using the Track Quality Index (TQI) as the primary indicator. TQI values from three consecutive inspection periods (2017–2019, 2019–2022, and 2022–2024) were analyzed to compute degradation rates (ΔTQI) across all track segments. The results were visualized through spatially distributed line graphs, enabling the identification of segments with progressive geometric deterioration. The analysis reveals a recurring pattern: several sections demonstrate improvement following tamping interventions, yet degrade again within a short period, indicating deeper structural or geotechnical issues. Particular attention is given to sections located on bridges, in tunnels, and near stations—areas associated with increased dynamic loads and limited substructure resilience. An overlay of maintenance data and structural object locations further strengthens the causal interpretation. The findings support the prioritization of high-risk segments for targeted interventions beyond routine maintenance. This degradation-based evaluation framework contributes to data-driven decision-making for long-term railway asset management, combining infrastructure condition assessment with spatial engineering analytics.