Track Quality Index for High Speed Track

Railroads have long faced the problem of formulating an objective measure of track quality, termed a Track Quality Index (TQI). However, the industry has yet to formulate a standardized TQI. The Federal Railroad Administration has mandated track safety standards. These could be interpreted as the lower bound of track condition, with track design standards representing the upper bound. A Track Quality Index addresses the condition of track between these bounds. Since track geometry serves as the forcing function on a free rolling rail car, it is the logical basis for formulating a TQI. Another advantage of track geometry is its ability to be automatically measured and recorded at high speeds. Research has shown that track geometry can be represented as a periodically modulated random process. In good quality, i.e., high speed track, a significant percentage of the maintenance performed is directed towards the deterministic components. It is therefore essential to include these in a TQI for high speed track.