Post-Construction Alignment Revision in Direct-Fixation Railroad Tracks

• Main Authors: Eungcheol Kim, Myungseob (Edward) Kim, Gabrielle Delos, Tyler Clark
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Sustainability
• Subjects: railroads; optimization; alignment; design; repair; post-construction
• Online Access: https://www.mdpi.com/2071-1050/11/21/6166

In railroad construction—in particular, direct-fixation tracks—a longitudinal concrete block known as a “plinth” is used to elevate the profiles of the railroad track from the aerial guideway (e.g., bridge deck). A post-construction alignment revision is often required if the plinth elevation surpasses its maximum tolerance after the concrete pour. In such cases, the plinth surface needs to be grinded to meet the design elevation, or a shim should be inserted underneath the rail pad to raise the profile elevation. Considering both sides of the rail plinths, vertical design factors, and performance specifications, re-optimization of the vertical profile is of great interest, but the process poses challenges and represents a practical research problem. An optimization model aimed at minimizing the cost of post-construction alignment repairs is proposed and a real-case numerical example is analyzed to check the effectiveness of the model.