Unstable subgrade and soft ground conditions of railroad roadbeds and embankments present a major dilemma for railroads and other private industries that own and / or maintain railroad tracks. Proper preparation and improvement of the subgrade and ground conditions are the base foundation for long lasting railroad roadbeds and embankments. A long term, extensive, and expensive maintenance program will be required if the existing or final subgrade is not prepared properly. Most of the railroad roadbeds and embankments were constructed many years ago and tracks are in operation. The majority of the existing railroad roadbeds and embankments have functioned satisfactorily until recently, when problems began to be noticed. These problems consist of, but are not limited to, settlements, embankment failure, piping and migration of fine particles, subgrade softening, and caving. The major challenge faced by railroads these days is maintaining existing roadbeds, embankments and tracks, in stable, safe condition, and in full operation. Any maintenance or repair of existing tracks must be performed with little or no interruption to train traffic and schedules. Proper preparation of the subgrade and ground conditions for new tracks and embankments can be accomplished more economically, compared to stabilizing existing roadbeds and embankments. Technology is available today to treat and / or stabilize most different subgrade conditions. A detailed planning and exploration program is required, as discussed in the latest revision of the AREMA manual Volume 1, Chapter 1. This paper presents different methods of subgrade treatment and ground improvement for both existing and new railroad roadbeds and embankments.
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