Railroad Embankment Stabilization Demonstration for High-Speed Rail Corridors

The development of high-speed railroad corridors in the United States is being considered by Congress as a fuel efficient and economical alternative to air or highway passenger travel. The existing infrastructure is, in many cases, suitable for freight traffic but not for the more exacting geometry standards of high-speed rail passenger trains. In many cases the proposed passenger service would use existing trackage heretofore carrying only slower moving freight trains (e.g., the newly opened service on the Northern New England Corridor (The Downeaster) between Boston, Massachusetts, and Portland, Maine). Instability in the roadbed can cause changes in track geometry at a rate unacceptable for safe or economical high-speed operation over existing lines. This project was conducted to demonstrate that existing ground stabilization techniques could be utilized to economically improve track performance for high-speed service. Rail traffic and the resulting limited track time available for maintenance in high-speed corridors dictate that embankment stabilization methods must be employed with minimum traffic disruption. The Federal Railroad Administration (FRA) Office of Railroad Development initiated a demonstration project to identify an unstable railroad embankment and effect a remedy. The purpose of the project was to develop experience with and demonstrate the capabilities of ground improvement techniques for reducing track maintenance requirements. The line segment selected for demonstration had a history of track settlement that continued after the line was rehabilitated for passenger service. After only a few years of renewed service, it became evident that the embankment was still subject to chronic settlement that required frequent resurfacing. A sub-surface investigation determined that a variable-thickness peat layer underlying the embankment caused the settlement.