The researchers developed a new method called Parametric Bootstrapping modified Weibull (PBW) to predict rail defect development more accurately. This method improves on the traditional 2-Parameter Weibull equation by allowing analysis of track segments with few defects. By applying PBW to over 300,000 track segments, they found that 77% had reasonable defect forecasting parameters, compared to only 11% using the traditional method. This means the PBW approach is more effective in estimating the likelihood of future rail defects, helping railroads plan maintenance better.