Image by Elvert Barnes licensed under Creative Commons.

It’s been about two years since Metro first introduced the 7000 series railcars, which were designed to expand the rail fleet and replace older cars. The hope was also that they’d be more reliable, and while there is still the occasional breakdown, they’re well on their way to serving that purpose.

Metro’s latest report card, “Vital Signs,” came out last month. It shows how frequently trains and buses were on time throughout 2016, how often those trains and buses broke down, and more. On the rail side of the house, the report says only 70% of all trips were considered “on time.” Lines were hit incredibly hard by SafeTrack; the Orange and Silver lines were only on time 33% and 35% of the time respectively in December during Surge 11.

The railcars themselves accounted for 65% of disruptions that caused delays of three minutes or more; the rest of the delays came from things like Metro police responses, sick passengers, and unattended bags, and track defects. It’s also worth noting the total number of railcar delays was down 13% compared to 2015.

The metric Metro uses to show railcar reliability is Mean Distance Between Delays (MDBD). Each car is expected to go at least 65,000 miles between causing a delay more than three minutes. The higher this number is, the longer the cars can go before breaking down. And when cars aren’t breaking down, it means fewer delays on your trip home, to the office, or wherever.

New cars are becoming more and more reliable

The 7000 series cars have been in the Metro fleet for about two years now. The first car was introduced on April 15, 2015, and the latest cars are still arriving weekly. Over this time the average 7000 car’s reliability has increased from a low of breaking down on average every 18,439 miles in July 2015 to delays happening every 115,492 miles in December of 2016.

This chart, which I made using data from the Vital Signs report through OpenDataSoft, shows the 7000 series’ performance since joining the system in terms MDBD:

The black horizontal line is Metro’s fleet-wide reliability target that each car is expected to be above.

Kawasaki, the cars’ manufacturer, is on the hook to make sure that the entire 7000 series reaches 200,000 MDBD - which would make them the most reliable cars in the fleet. The 6000s currently hold the title of most reliable fleet, and averaged 108,194 miles between delays during 2016..

The 200,000 MDBD threshold isn’t something that the cars were intended to reach immediately (although that would have been great). When new cars join a system, there are always little software and hardware issues. Glitches or car defects that didn’t show up in testing may have become apparent once the 7000s started daily use. The gradual increase in reliability since introduction is a sign these issues are being worked out.

The 7000s are performing well compared to other cars in the fleet

The interactive graphic above shows the MDBD reliability of all six series of railcars --1000s, 2000/3000s, 4000s, 5000s, 6000s, 7000s -- over time since 2008.

As I mentioned above, the 6000s have consistently been quite reliable. But compared to the other car series, the 7000s have already moved into second place in terms of miles between delays .

As you can see, Metro’s railcar reliability largely dropped off in 2014. The reason is the opening of the Silver Line, which stretched the railcar fleet and meant more cars had to run in service for longer, with less downtime for repairs and preventative maintenance.

7000 series trains mean fewer 4000s and 1000s (which is a good thing)

Overall, challenges to managing the railcar fleet should get easier to deal with as the 7000’s continue to arrive and the 4000 series cars, the least reliable, leave.

In addition to early retirement for the 4000s, Metro started retiring its 1000s April 12, 2016. With these two fleets gone, trains will no longer have certain cars that can only be placed in the middle of the trains (1000s/4000s), meaning it will be easier to create trains for service in the rail yards instead of having to shuffle them around. Also, it will be easier to streamline maintenance since Metro will only need unique parts for four types of railcar instead of six.

The 7000s are still on the up in terms of reliability, and there are other ways to look at how well they’re doing. There’s a different industry metric Metro could publish, Mean Distance Between Failure (MDBF), which records how far the railcars go in between a breakdown of any sort. This metric is more transparent than MDBD since it records not only all the issues that cause 3+ minute delays, but also other failures that don’t delay a train. For instance, broken AC in a railcar won’t delay a train, so it won’t get recorded by the MDBD metric - but it would be recorded by MDBF. It’s a better metric to show the railcars’ reliability as a whole.

As more and more 7000s come into service as their overall reliability increases, delays that riders incur should begin to diminish (although only once SafeTrack wraps up). Rail delays are few but lengthy - and what SafeTrack is beginning to address - but railcar delays are many. Decreasing those car delays just a few percentage points would be the second step in providing passengers a more safe and reliable ride to wherever their destination may be.

Stephen Repetski is a Virginia native and has lived in the Fairfax area for over 20 years. He has a BS in Applied Networking and Systems Administration from Rochester Institute of Technology and works in Information Technology. Learning about, discussing, and analyzing transit (especially planes and trains) is a hobby he enjoys.