Development of ice-bonded ballast in sub-freezing temperatures and its effect on maintenance operations during a winter rail break

Sub-freezing temperatures result in ice formation within the ballast layer of railroad track. Given the proper moisture and fouling conditions, the retained moisture bonds ballast particles together changing the mechanical properties. For above-freezing temperatures, longitudinal track resistance (f0) to restrain the track system has been quantified by crosstie-type and ballast condition (e.g., consolidated or disturbed). Sub-freezing temperatures produce the largest differentials between the rail temperature and RNT (rail neutral temperature) [i.e., differential temperatures (dTs) exceeding 30⁰C (100⁰F)] producing tensile stresses that can exceed the strength of the rail at defects, causing the rail to break and a gap to open. This study quantified the effect of frozen ballast on shear strength, f0, and rail gap size using laboratory experimental data and Illi3D, a field-validated finite element model (FEM). The laboratory data were transformed into f0 using a novel method developed in this study and then incorporated into Illi3D to simulate single rail breaks and quantify the effect ice-bonded ballast has on rail break gap. Clean and fouled-ballast shear strengths exhibited different behaviors when frozen. The f0 of fouled-frozen ballast increased two to five times, and the gap size reduced ~67% and 50% for timber and concrete crosstie track, respectively. The fastening system accounted for the displacement in frozen conditions. Additionally, a novel laboratory apparatus was developed to isolate the rail-anchor interaction and measure the force required to initiate slip. The laboratory study investigated the effect of worn anchors and rail on slip strength. A reduction up to 20% of ultimate slip strength was observed when considering component wear. The study also looked at the effect of loading rate and found a 30% reduction in ultimate slip strength when a rapid load is applied as compared to quasi-static loading.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Froehlke, Coleman

Contributors dc:contributor

• Edwards, John Riley
• Dersch, Marcus S

• Railroad
• Ballast
• Geotechnical
• Rail Neutral Temperature
• Direct Shear Test

Statement dc:rights

• Copyright 2025 Coleman Froehlke

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/132703

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/132703