Washington Post: (Metrorail) Crash Was Supposed To Be Impossible

[marmar]

THE PROBE: Experts Suspect Failure Of Signal System, Operator Error

By Lyndsey Layton
Washington Post Staff Writer
Tuesday, June 23, 2009


Experts familiar with Metro's operations focused last night on a failure of the signal system and operator error as likely causes of yesterday's fatal Red Line crash.

Metro was designed with a fail-safe computerized signal system that is supposed to prevent trains from colliding. The agency's trains are run by onboard computers that control speed and braking. Another electronic system detects the position of trains to maintain a safe distance between them. If they get too close, the computers automatically apply the brakes, stopping the trains.

These systems were supposed to make yesterday's crash impossible.

But four years ago, in an episode eerily similar to yesterday's, the signal system briefly failed in the tunnel between Foggy Bottom and Rosslyn, forcing two quick-thinking operators to stop their trains manually to avoid a crash.

In the June 2005 incident, the operator of one train noticed that he was getting too close to the train ahead. The signal system was telling him the track was clear, but he hit the brakes. The operator of a third train on the line hit the emergency brakes on time, too.

Metro officials were stunned by the events, which they said at the time had not happened before, and launched an investigation. It was unclear last night whether they ever found a cause. ........(more)

The complete piece is at: http://www.washingtonpost.com/wp-dyn/content/article/2009/06/22/AR2009062203261.html?hpid=topnews

[FSogol]

1. The problem with complex controls is that over time, they are modified,

disabled, or break. Often the controls are more complex and the people maintaining them are poorly trained. Every system on the Metro Rail should be tested and recommissioned.

[marmar]

3. And I thought Metro was pretty meticulous with the maintenance.....

..... Seems like every time I'm in DC a line is being worked on.

[FSogol]

5. They are under-funded. n/t

[Blue_Tires]

8. they had me fooled with the $$$$ they clean up for parking....

[babylonsister]

2. I hope the operator wasn't tweeting.

That's happened all too often.

Very sad either way.

[Captain Hilts]

11. They obviously weren't paying attention. I've ridden that route MANY times. Visibility is good. nt

[KharmaTrain]

4. Computers Are Human

When I saw the accident...two trains on one track (with a second track next to it), the first thing I thought was operator error. Someone or something didn't switch where it should have and by the time it was detected (if it was noticed at all) it was too late.

Despite all our sophisticated technology, it still requires human beings to maintain and have the ultimate control. Machinery breaks down, computer chips malfunction and software glitches. It's a sad tragedy, but in a world that relies on technology, it's an inevitable byproduct of it.

[justiceischeap]

9. It's not uncommon for several trains to be on the same track

They were both headed in the same direction. When I ride in the mornings (the red line) I often am stuck waiting for another train to pull away from a station.

What I'm wondering about is a communication error. I was stuck in that mess last night and there was a train ahead of us at Union station who just sat on the tracks because there seemed to be a "communication problem" according to our engineer (meaning his comms weren't working). Makes me wonder if that applies to the train that plowed into the stopped train.

[Stuart G]

6. 70 years ago, they installed failsafe controls in the Chicago Subway ...

and they worked. No crashes ever..But the systems could not be over-ridden, except by shutting the whole system down. I read about those systems. They involved mechanical T looking like things. They stuck out from the tracks, and stopped electricity..
(I used to sit in the front as a kid and watch the train go)

So in their wisdom, the transit people set up a new system. better system. Some kind of cab control things. The train engineer could override the sytem, and drive the train forward at slow speeds...sure...

Guess what? Crashes, every so often one train hit another...Lives lost...severe injuries etc...

great new system...

[MineralMan]

7. Such automated systems encourage operator errors.

Since they work almost all the time, human operators tend to forget to pay attention. Then, when the system doesn't work properly, they aren't tuned into the operation of what they're operating. Boom!

The solution is to included some feature requiring that the operator affirm that attention is being paid at regular intervals. A push-button response to a random signal is adequate.

Otherwise, operators tend to find something other than running the system to fill their time.

[Captain Hilts]

12. There are stories of how there have been a few cases drivers averted crashes.

I guess we don't call them 'motormen' as in NYC.

[AngryAmish]

10. And what happens when they are going 220 mph? I think we just killed high speed rail.

[marmar]

13. The 200 mph trains in Europe and Japan seem to work just fine while staying on the track.....

n/t

[AngryAmish]

14. Like this?

This is kinda a cheap shot - there has been ONE crash.

[marmar]

15. Kind of a cheap shot? One crash over the years out of thousands of high-speed sorties every day....

..... BY FAR the safest mode of travel.