Photo by japharl on Flickr.

In September 2008, I concluded that Metro’s rail reliability lagged compared to its peers. Using reported breakdowns and delays in May 2008, Metro appeared less reliable than even the worst line in New York City, breaking down about twice as much.

Taking new data from May 2010, Metro’s reliability appears to have deteriorated even more, with twice as many trains being taken out of service for mechanical problems, 30% more trains being removed from service for door problems, and more than three times as many trains that cannot be placed in service due to managerial failures such as not having railcars or operators available.

On the bright side, there were fewer trains delayed without being taken out of service.

Here’s a chart of how many trains were taken out of service, divided by cause:

Here’s the coded data and the spreadsheet. The analysis method is described here.

Michael Perkins blogs about Metro operations and fares, performance parking, and any other government and economics information he finds on the Web. He lives with his wife and two children in Arlington, Virginia.