Posts about Derailment

My coworker left the office at about 5:00. At this point, the Green Line had been blocked by the derailed train for 15 minutes already, though neither of us knew that.

The news of the derailment, apparently broken by the Prince George's County Fire Department over Twitter, was first reported at about 5:08, probably about the time my colleague (we'll call him "B") was getting on the Red Line.

Slightly earlier, at 5:00, Metro tweeted that passengers on the Green Line would experience "significant delays" due to a disabled train near West Hyattsville. Following along on Twitter, it was not immediately clear to me that this was a different event from the single-tracking around a disabled train at Fort Totten (the next stop south of West Hyattsville).

Metro sent out an email to Metro Alerts announcing the derailment at 5:25, 40 minutes after the derailment. I don't know what announcements they were making in the stations. But by then, B was probably amidst a sea of unhappy, ill-informed riders at Fort Totten.

According to Metro spokesperson Dan Stessel, the first shuttle bus arrived at 5:20, but bus bridges take time to set up. By 8 pm, Metro was using over 40 buses in the shuttle operation.

By this time, it was probably apparent to everyone at Fort Totten that the commute was not going to be a smooth one. My coworker, B, stayed with the mob of passengers, hoping for a shuttle bus toward Greenbelt.

I was stuck at the office. I had to finish working on a few things before I could leave, but I was monitoring the Metro situation. I knew that my commute was going to be rough.

Finally, I finished my tasks, checked Metro's trip planner, and left the office at 6:43, 1 hour and 43 minutes after B. I walked down to the nearest Metrobus stop on route F4, and caught a bus bound for New Carrollton.

The bus was crowded, though based on trips I've taken in the past, not by a whole lot more than usual. At Prince George's Plaza, I hopped off and headed for the train platform.

A train was sitting on the platform normally used for Greenbelt trains, but WMATA workers were directing everyone over to the Branch Avenue platform. The transit police officers on the Branch Avenue platform didn't know why we were all being directed there, but eventually discovered that another Greenbelt train would be arriving there shortly.

Risking it, I rushed back up to the mezzanine and then down to the Greenbelt platform, I managed to cram myself onto the first train just before the doors closed, and we headed off to Greenbelt.

I arrived at Greenbelt at 7:35, only 52 minutes after I'd left my office. While waiting on the 7:40 bus to my apartment, I saw B walking by. He'd just gotten off the same shuttle train I'd been on. He stopped for a moment to chat, and recounted that he'd been commuting since 5:00, and still wasn't home.

My trip from the office to Greenbelt took 1 hour 43 minutes less than his. What was the difference? I took a regularly scheduled bus instead of fighting for a spot on a shuttle.

In fairness to B, he was already at Fort Totten before he discovered the snafu playing out a few miles up the Green Line. But what it suggests is that if he'd gotten back on the Red Line and ridden to Silver Spring, he could have caught the F4 (it runs about every 20 minutes) and gotten to Greenbelt much earlier than he did.

In my experience, waiting on the bus bridge is almost never faster than finding an alternate, regularly scheduled service.

But it's not always that simple. The F6 bus runs from Fort Totten to Prince George's Plaza. But because of the mass of desperate commuters at Fort Totten, it would have likely been swamped, too.

The real trick is to go to a station not full of displaced riders. Know the alternatives for getting to your destination, not from wherever you got offloaded. It may be faster to get back on the train and head to a different station.

For example, you can get to Greenbelt station on Metrobus routes C2 (from Wheaton), R12 (Deanwood), G12, G14, and G16 (New Carrollton), and also on TheBus routes 15X and 16 from New Carrollton.

For me, the F4 proved to be a huge time saver. I saved over an hour and a half simply by having a Plan B.

No matter how hard Metro tries, something will go wrong sometime; it's inevitable. If you take a few minutes right now to figure out some alternate routes home, you may save yourself a lot of pain one day in the future.

The train was bound for White Flint station. White Flint was to be the terminal because Twinbrook, Rockville, and Shady Grove remained closed due to snow accumulation on the tracks. After stopping at Farragut North to allow passengers to board and alight, the train began to head north toward Dupont Circle. Immediately north of the Farragut North platform, there is a pocket track.

Click to enlarge.

This pocket track is typically used to store trains or allow them to turn back in the direction from which they came. In some cases it is used to allow trains to switch between the inbound and outbound track.

For some reason, the switch was set to allow the northbound train onto the pocket track (at "A" in the diagram). It is unclear at this time why the switch sent the train into the pocket. However, the operator continued traveling toward Dupont Circle at a low rate of speed. This low speed would have been enforced by the Automatic Train Control (ATC) system.

The pocket track is about 600 feet long, the same length as a Metro platform. At the northern end of the pocket (at "C" on the diagram), is another switch. This switch enables trains in the pocket to switch to Track 1 or Track 2. At this point there is a signal and derailer. Since the derailer was engaged, the signal should have been red - assuming there were no mechanical or electrical problems with the device. The train operator should have been able to see the red signal when the train entered the pocket (at "B"), at least 600 feet away.

Now, the signal at "C" would only show a clear to proceed aspect if several conditions were met: The switch at "C" is set to the right, the switch at "D" is set for the pocket turnout, and the track immediately north of "D" is clear. Or, the switch at "C" is set to the left, the switch at "E" is set for the pocket turnout, and the track immediately north of "E" is clear.

Otherwise, the signal would show a red aspect and the derailer would be engaged.

The derailer works by literally derailing the train. Basically, if the switch is set in a manner which will direct the train into danger, the derailer is engaged. It is automatically operated by the signal system and, when engaged, is placed flush against one of the running rails.

It essentially acts as a ramp for one of the wheels, lifting it up to the level of the rail. It then channels that wheel toward the outside of the track, which causes the wheel truck to drop so that one wheel is off the trackbed and the other wheel is in between the running rails. This creates additional friction, and should stop a train even if braking power has been lost.

Of course, derailers can fail. One of the most tragic cases occurred on September 15, 1958 when a commuter train bound for the ferries to New York City ran off the end of an open drawbridge. The accident killed 48, including Kurt Vonnegut's brother-in-law. He references this accident in his works.

As the train approached the CRRNJ Newark Bay Lift Bridge, it ran through three red signals and hit a derailer 450 feet before the bridge. Despite being derailed, the two locomotives and three passenger cars skidded off into the bay.

In today's derailment, however, the derailer worked as intended. In fact, not only did the derailer prevent a collision or damage to misaligned switches, it also prevented the train from fouling either main track. However, while this event saw the safety system avert potential disaster, it is not clear why a potentially dangerous situation was allowed to progress so far. Many questions remain.

All of Metro's riders can hope that the root cause will quickly be determined so that future instances can be prevented.