Inside the Analysis

The Washington Post analyzed Metro statistics to evaluate the agency's programs for buying new rail cars and overhauling older ones. Metro officials provided data on miles traveled, delays and mechanical failures for each brand and type of rail car, ranging from the oldest Rohr cars built in the 1970s to the latest-model CAF cars. The Post calculated statistics on breakdowns and on mechanical problems for each type using the most recent full year of data, through April.

The newspaper also analyzed Metro's efforts to rebuild escalators using agency statistics on units rehabilitated since 2000. For 128 escalators, The Post compared the percentage of time they were operating before the overhauls with their performance over an 18-month period ending in December. Metro did not provide statistics for every escalator because in some cases it did not have pre-renovation figures and in others the renovation had been completed too recently to be evaluated.

In addition, The Post compared escalators serviced by Metro employees with those serviced by private contractors, looking at the mean time between breakdowns and the mean time required for repairs. The data covered two years, ending in October, the most recent month for which Metro provided statistics.