Application of Geocell Track Substructure Support System to Correct Surface Degradation Problems Under High-Speed Passenger Railroad Operations, Zaremski, et al (2017)

Field test on problematic section of Amtrak's NE Corridor demonstrated how Neoloy Geocells reduce the rate of track geometry degradation and track surface maintenance by factor of 6.7x

Description

A full scale in-track field evaluation of Neoloy (NPA) Geocell was performed under actual main line conditions on Amtrak track on the heavily trafficked Northeast corridor. NPA geocells were used to mechanically stabilized a problematic section of track, which suffered significant mud pumping and track geometry degradation from poor subgrade.

Data Collection

Comprehensive track measurements between a track rebuild with a hybrid solution of NPA geocells and geogrids compared to a conventional structure demonstrate how new generation geocells improve track geometry and reduce maintenance. Data was collected by Amtrak track geometry vehicles, from pre-build and post-build track measurements  including data from pressure cells installed in the track subgrade.

Geometry measurement data of the rebuild section without geocell stabilization experienced considerable track geometry degradation and variations within 6-7 months after the reconstruction (which included improved drainage, good track substructure, and clean ballast).

Results

In the NPA geocell stabilized section, subgrade pressure were half of those in the control zone (no geocell). Track geometry variations in the NPA geocell zone were significantly smaller – for left and right track, cross-level data and the TQI standard deviation (shown below):

TQI standard deviation variation before and after track rebuild (Oct 15) in unreinforced control (top) and geocell zones (bottom)

The data supports results that show that the NPA geocell improved track support, reduced bearing pressures on the subgrade and provided improved track geometry performance over time. Notably, the rate of track geometry degradation was reduced, thereby extending the time between surfacing maintenance cycles by a factor of 6.7x. This results in marked maintenance savings to Amtrak and an exceptional ROI on the project.

 

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