Fatigue Performance Characterization of Direct Fixation Systems Under Heavy Rail Transit Loading Conditions
(Room M 100 C)
24 Sep 19
10:30 AM
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11:00 AM
Tracks:
AREMA Technical Sessions By Functional Group- Track, Technical Sessions By Day- Tuesday
Railway track infrastructure typically consists of a fastening system, crosstie, and a ballasted substructure. However, in the rail transit domain, direct fixation (DF) and slab track systems are utilized in certain instances for their high level of track stability, improved ride comfort, and precise control of alignment. Of specific interest with DF systems is the adequacy of traditional rubber bonded fasteners to the rail transit loading environment, especially in light of several recent failures. Considering the stress state of the numerous components encompassing a DF system, the following stresses are thought to have a critical role in the damage of DF components: residual stresses caused by anchoring of the system to the substructure, cyclic stresses from train revenue service, and shear stresses resisting longitudinal action. In response, researchers at the University of Illinois at Urbana-Champaign (UIUC) conducted a field investigation and developed both static and fatigue models to quantify the load behavior and determine the adequacy of fastener components. The study was conducted during peak revenue service hours on a heavy rail transit system in the eastern United States. The variance in track response across similar track geometry and rolling stock operation suggests that direct fixation track performance can vary, which is likely associated with rail seat conditions (e.g. geometry and tolerances). Improvements to the design of DF systems are currently underway, and this presentation will summarize both the results of static and fatigue experimentation and propose a path forward for the design of new, optimized DF fastening systems. *Missed this Session or want to view it again? Stop by the VirtualAREMA kiosk located in the Registration area to purchase this product today!