Welcome to DU! The truly grassroots left-of-center political community where regular people, not algorithms, drive the discussions and set the standards. Join the community: Create a free account Support DU (and get rid of ads!): Become a Star Member All Forums Issue Forums Culture Forums Alliance Forums Region Forums Support Forums Help & Search
 

FarCenter

(19,429 posts)
Mon Jul 8, 2013, 11:05 AM Jul 2013

Lac Megantic: Death toll rises in Quebec train derailment explosion

Ravaged site is now being treated as a “crime scene” as the railway says someone shut down a locomotive keeping the brakes on.

Ed Burkhardt, chairman of the Montreal, Maine & Atlantic Railway, said Sunday night that the train’s sole engineer shut down four of the five locomotive units on the train, as is standard procedure, in the neighbouring community of Nantes before heading to Lac Mégantic to sleep. Burkhardt said the next engineer was probably due to arrive at daybreak.

But someone managed to shut down the fifth locomotive unit, he said. The railroad alleges someone tampered with the controls of the fifth engine, the one maintaining brake pressure to keep the train stopped.

“If the operating locomotive is shut down, there’s nothing left to keep the brakes charged up, and the brake pressure will drop finally to the point where they can’t be held in place any longer,” Burkhardt said.

There are two ways to shut down the fifth unit: There’s an emergency lever on the outside of the locomotive that anyone wandering by could access. Or, there are a number of levers and buttons inside the unlocked cabin.

Both means were used, said Burkhardt.


http://www.thestar.com/news/canada/2013/07/07/lac_megantic_death_toll_rises_in_quebec_train_derailment_explosion.html

Since there was a fire in one of the locomotives which was extinguished by the Nantes fire department, it is possible that one of the firemen shut down the locomotive.

However, leaving a train unattended without setting the manual brakes on enough individual cars to hold the train appears to be an unacceptable operating practice. There should also have been a derailer placed at the downslope end of the train so that if it starts to move, it would leave the tracks.
12 replies = new reply since forum marked as read
Highlight: NoneDon't highlight anything 5 newestHighlight 5 most recent replies
 

FarCenter

(19,429 posts)
4. I'm not sure what happens if the pressure bleeds down slowly
Mon Jul 8, 2013, 11:18 AM
Jul 2013

If the main brake line pressure drops suddenly, as in a decoupling of a car, the valve disconnects the brake line and uses the local pressure reservoir in the car to apply the brakes. They stay applied until the pressure in the car leaks down.

So either enough in car reservoirs leaked down to let the train move, or at some point in the main brake line leaking down the brakes in the cars are not fully applied. There were reports of seeing sparks from the rails as the cars came into town, so some cars may have had brakes applied.

Not sure what the grade from Nantes to Lac Megantic is, but part of the Nantes siding is 0.7 grade, and I've seen an estimate that the gravitational force on the train would have been 30 to 40 tons when parked.

 

cali

(114,904 posts)
6. just want to say I really appreciate your posts on this.
Mon Jul 8, 2013, 11:20 AM
Jul 2013

particularly the clear way you explain bewildering (to me) technical aspects.

Again, thanks, FC

 

HooptieWagon

(17,064 posts)
9. Yes. Air pressure from the locomotive keeps the brakes released.
Mon Jul 8, 2013, 12:57 PM
Jul 2013

When the air pressure is reduced or vented, the reserve air tanks on each car apply the brakes. The Westinghouse brake system has been in use for well over 100 years, although I don't think its still used on passenger trains. It is a reliable system. I don't know what happened in this case.

mainer

(12,013 posts)
2. I'm astonished that something this dangerous is left unattended and unlocked.
Mon Jul 8, 2013, 11:09 AM
Jul 2013

Anyone could access it. You'd think there'd be a hand-over from engineer to engineer.

bluedigger

(17,077 posts)
3. It's starting to look like an event caused by a chain of procedural errors.
Mon Jul 8, 2013, 11:14 AM
Jul 2013

From what I have gathered, there was a fire on one of the engines earlier that evening, which local responders put out. It isn't clear if the train was subsequently inspected by rail officials, although I think they have claimed it was. Either they missed the fact that the FD had shut down the train, not understanding the implications, or it wasn't inspected at all. That seems to be the point where things went tragically wrong.

pinboy3niner

(53,339 posts)
10. REUTERS: Fire was doused on train before it smashed into Quebec town
Mon Jul 8, 2013, 02:21 PM
Jul 2013
By Richard Valdmanis and Julie Gordon

LAC-MEGANTIC, Quebec | Mon Jul 8, 2013 2:03pm EDT

(Reuters) -

...

Nantes Fire Chief Patrick Lambert said his crew had switched off the locomotive late on Friday as they extinguished a "good-sized" blaze in the motor, probably caused by a fuel or oil line break in the engine.

"We shut down the engine before fighting the fire," he told Reuters in an interview. "Our protocol calls for us to shut down an engine because it is the only way to stop the fuel from circulating into the fire."

The tanker train's operator, the Montreal, Maine & Atlantic Railway, said the engineer had parked the train in Nantes on Friday night and left one locomotive running to ensure the air brakes worked properly.

The company's chairman said the brakes will not work if a train is switched off.

"If the operating locomotive is shut down, there's nothing left to keep the brakes charged up, and the brake pressure will drop finally to the point where they can't be held in place any longer," Ed Burkhardt told the Toronto Star.

...


Lambert said once the blaze was out, the Nantes fire service contacted Montreal, Maine & Atlantic Railway. "We told them what we did and how we did it," he said.

Asked whether there had been any discussion about the brakes, he replied: "There was no discussion of the brakes at that time. We were there for the train fire. As for the inspection of the train after the fact, that was up to them."

...


http://www.reuters.com/article/2013/07/08/us-train-idUSBRE96505L20130708


 

FarCenter

(19,429 posts)
11. In the US, it would be against regulation to depend on air brakes
Mon Jul 8, 2013, 02:54 PM
Jul 2013
Securement of unattended equipment. A train's air brake shall not be depended upon to hold equipment standing unattended on a grade (including a locomotive, a car, or a train whether or not locomotive is attached). For purposes of this section, "unattended equipment" means equipment left standing and unmanned in such manner that the brake system of the equipment cannot be readily controlled by a qualified person.


http://books.google.com/books?id=aLzZB07raxwC&pg=PA606&dq=unattended+train+hand+brake+regulation&hl=en&sa=X&ei=FgnbUZerCdK44AOb04CwCQ&ved=0CDUQ6AEwAA#v=onepage&q=unattended%20train%20hand%20brake%20regulation&f=false

There follow regulations for setting hand brakes and depressurizing the air brakes before leaving the train.
Latest Discussions»General Discussion»Lac Megantic: Death toll ...