Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Saturday, November 17, 2012

Midland Grade-Crossing Crash: More on event recorders

The NTSB has a go-team at the site of the wounded veterans' rail tragedy this week at a grade crossing (location: Garfield Street) in Midland, TX

Investigators are talking to witnesses, examining signals at the grade crossing, studying video from personal cameras and a patrol car, and downloading event-recorder data from the Union Pacific's head-end locomotive, which includes forward-facing video and probably external audio as well.

So once again, tragically, event recorders are in the news. I've blogged about the role of VDRs and FDRs in investigations of the Costa Concordia wreck, the SuperJet 100 cliffside crash, Delta Mariner's bridge allision, and the Air France Flight 447 crash. 

In the case key information about the moments leading up to the crash should be preserved, unlike in the collision of two UP freight trains this summer in Goodwell, OK, which reportedly destroyed the event recorders in both head-end locomotives. (The NTSB hasn't released more than a preliminary report on the Goodwell crash, and there's no public docket that collates other information, so that's about all that we have for now about that mainline rail disaster.)

Readers may be curious about the cameras deployed on engines. I don't see information specific to the UP locomotives, but from a recent passenger-rail contractor solicitation for locomotive upgrades, here's a photo of a typical locomotive dashboard prior to installation -- I find it helpful because it shows the engineer's view. 
Here's the forward-facing camera as installed. It feeds video information to a recorder in a crash-resistant case elsewhere in the cab. That recorder also stores sound from an external microphone as well as and instrument readings.
These are not necessarily HD cameras, but can show the color of signal lights almost a half-mile ahead.

NTSB investigators also look to the larger setting, and events well before the crash. Their timeline might include a chronology of other crashes at the Garfield grade-crossing, along with notes about changes in safety procedures or equipment. It's not clear whether this location's status as a "quiet zone" made any difference, given the automatic crossing gates and the fact that the engineer did sound the air horn before the crash. Lights and grade-crossing gates are meant to provide motorists with 20 seconds of warning -- did they?

According to news reports, previous rail-vehicle crashes at this location had occurred at speeds less than half that of this train, which reportedly was moving at 62 mph (which, as far as we know, complied with speed limits at this location in Midland). So one question might be whether safety procedures kept pace with changes in railroad speeds.