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Precise Data About Train’s Speed At Time Of Crash Will Come From Onboard Recorder

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Precise Data About Train’s Speed At Time Of Crash Will Come From Onboard Recorder


By Tom Avril, The Philadelphia Inquirer (TNS)

PHILADELPHIA — When you get right down to it, it was a question of physics.

At the site of the Amtrak derailment on Tuesday, the track had a curvature of 4 degrees. Imagine a giant circle with a diameter of nearly 2,900 feet, more than a half-mile. The track’s path would trace the outline of that circle.

The track also had a “superelevation” of 5 inches, meaning the outer rail was5 inches higher than the inner rail.

Given those parameters, a locomotive pulling seven Amtrak-size cars could safely travel up to about 55 mph, said Pennsylvania State University engineer Steve Dillen, who performed a rough calculation at The Philadelphia Inquirer’s request.

Early indications are that it was going nearly twice that fast, a National Transportation Safety Board member said Wednesday at a news conference.

Exactly how much faster will have to wait for detailed data from an onboard “event recorder,” analogous to what is known on airplanes as a black box. On trains, these devices electronically track speed, direction, distance, throttle position, and the use of brakes, among other data.

“It’ll tell them everything that train did,” said Danny Gilbert, a rail safety consultant based in Roanoke, Va.

Such recorders have been required on trains for years, but data sometimes have been lost in violent accidents. In 2005, the Federal Railroad Administration enacted rules requiring the devices to be crash-resistant.

Speed is typically measured using an axle-mounted generator that pulses with every revolution. Such generators often are mounted on more than one axle; their outputs can then be compared to correct any issues with slipping and sliding. The data is then transmitted to the event recorder.

It was not immediately known who made the box or boxes on the Amtrak train that derailed. Mayor Michael Nutter said they had been taken to an Amtrak facility in Delaware for analysis.

The section of track where the train derailed had a 50 mph speed limit.

Dillen, who coordinates the rail transportation engineering program at Penn State Altoona, said an additional 5 mph would probably be OK. Beyond that, he could not say.

Determining the exact tipping point, he said, would require a more detailed analysis involving the train’s center of gravity.

(c)2015 The Philadelphia Inquirer, Distributed by Tribune Content Agency, LLC.

Multiple injuries are reported during an Amtrak crash of a northbound train in Port Richmond on Tuesday, May 12, 2015, in Philadelphia. (Tom Gralish/Philadelphia Inquirer/TNS)



  1. Alvin Harrison May 17, 2015


    If you are looking for an example of some important system in to the “regular” American that our bought and paid for legislators neglect because it not that important to the Corp/1%….you need look no further that our rail system. There are many other “systems” we see falling apart because they are of no use to the rich….our education system….our highway system…I could go on.

    The article below is scary if you regularly use our rail system to commute or travel. Stories of pieces of this system dating back to the civil war abound….$21 billion needed to replace parts that have outlived their intended service life…The system, by all accounts is abysmal…and getting worse daily. Expects stories of train disasters to increase in frequency, as the system continues and accelerates it’s deterioration.

    But wait you say…the Corp /1% would not want lose their myriad of products that they ship by rail in a disaster. Those products are insured. But what about the property destroyed when a tanker train spews it’s chemicals all over the surrounding countryside. Insurance hopefully will cover most of that too. What is not covered is the lives lost and lives disrupted by these disasters. Please do not say insurance covers that…tell that to those who died and their loved ones if you have no heart. The powers that be will blame the people driving and servicing this decrepit network, in which case the families of those who die have no one to sue. Even if they can sue, it is a long drawn out process, and they payout is cheaper than for corporations paying their fair share of taxes that would provide the money for infrastructure maintenance.

    This is yet one more reason we need to get rid of our legislators that take money from the rich and powerful. We are being shortchanged and cheated. The state of Maryland said there was not enough money to add $11 million to the education budget there…then they added $31 million to the budget to incarcerate juveniles in the corporate run jail system. The rail system needs $21 billion just to make sure bridges and switches operate correctly and to replace aging parts…our congress cut the rail subsidy by $251 million to $1.1 billion. The FAA’s budget is to be increased….the rich do not want their jets in jeopardy or the planes they use to fly around the country making those big deals crashing with them in them.

    Why Americans takes this I have NO idea. If the rich do not need or use something it is forgotten and neglected. I would bet 90% of our problems as Americans could be solved by one simple thing….removing big money and lobbies from our political system and making this country, once again, function as it was designed….By the people and for the people.

    1. Alvin Harrison May 17, 2015

      Update….still no evidence the train was speeding…now it is that something shattered the windshield…must be terrorists.


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