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I really couldn't believe it when I got the first message (I get transportation alerts from the city) saying one train was on top of the other.  And then when I saw the early pictures, I had to pass my iPhone around to four other people who couldn't believe it either.

Per BBC News just now on tv, there may still be people trapped inside.

I was hearing that a few hours ago, around sundown, but wasn't sure whether it was still the case.  I'm still hearing helicopters going overhead quite a bit, could be medics or police.

I can't for the life of me figure out how it would've happened.  There are supposed to be automatic relays to stop trains from getting to close to each other.  And the it looks like the second train was moving really fast:

But even if the signal system failed to stop the train, the operator should have intervened and applied emergency brakes, safety experts familiar with Metro's operations say. The position of the second train after the crash -- the fact that its first car came to rest atop the other train -- indicates that the second train was traveling at high speed. In the section of track where the accident occurred, the maximum speed is supposed to be 58 mph. Metro officials would not say how fast the trains were going because of the ongoing NTSB investigation.

I watched part of the NTSB briefing, and the board member said she didn't know whether it was going to be possible to tell how fast the train was going, because she wasn't sure what kind of equipment was on the trains in question, or whether it survived the crash.  I'm reading that the Red Line is the oldest of the system's lines, and the trains may have more outdated equipment than the newer ones on, say, the Green Line.

by the stormy present (stormypresent aaaaaaat gmail etc) on Mon Jun 22nd, 2009 at 11:44:21 PM EST
[ Parent ]
How true is it that the train would have to be moving really, really fast?  Something the weight of a train has a lot of momentum at 58mph. DoDo?
by Sassafras on Tue Jun 23rd, 2009 at 02:30:43 AM EST
[ Parent ]
Yes, it should also depend on the structural design of the front of the car.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Wed Jun 24th, 2009 at 01:37:26 AM EST
[ Parent ]
Sounds highly unlikely. A competent crash engineer should be able give an answer irrespective of what instruments aboard were or were not functioning.

--
$E(X_t|F_s) = X_s,\quad t > s$
by martingale on Tue Jun 23rd, 2009 at 02:58:26 AM EST
[ Parent ]
Signalling system fault?

A man of words and not of deeds is like a garden full of weeds; a man of deeds and not of words is like a garden full of turds — Anonymous
by Migeru (migeru at eurotrib dot com) on Tue Jun 23rd, 2009 at 04:30:12 AM EST
[ Parent ]
But even with a signal failure, he should been able to look out the front of the car and see it coming, thus at least being able to slow down or stop.  Metro trains can be stopped pretty quickly.

Conservatives want live babies so they can raise them to be dead soldiers. - George Carlin
by Drew J Jones (myfriends@thisispancakes.com) on Tue Jun 23rd, 2009 at 10:46:44 AM EST
[ Parent ]
Signal failure + driver failure? This sort of disaster happens when all your failsafes fail. It's the third or fourth thing that goes wrong that gets you.
by Colman (colman at eurotrib.com) on Tue Jun 23rd, 2009 at 10:50:42 AM EST
[ Parent ]
Yep, sounds like the infamous and still not really solved Moorgate crash.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Wed Jun 24th, 2009 at 01:38:59 AM EST
[ Parent ]
Moorgate tube crash - Wikipedia

The Moorgate tube crash was a railway disaster on the London Underground, which occurred at 8:46am on 28 February 1975.

A southbound train on the Northern Line (Highbury Branch) crashed into the tunnel end beyond the platform at Moorgate station. Forty-three people were killed at the scene, either from the impact or from suffocation, and several more subsequently died from severe injuries; the greatest loss of life in peacetime on the London Underground, and the second greatest loss of life on the entire London Transport system (the first being the 7 July 2005 London bombings). The cause of the incident was never conclusively determined.[1]



*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Wed Jun 24th, 2009 at 01:39:57 AM EST
[ Parent ]

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