Hello all,
You might want to look into the thread on the Trains forums:
http://cs.trains.com/trn/f/111/t/218974.aspx?sort=ASC&pi332=1
NW
The articles I have read said the train was on a grade, and a number (unspecified in the article) of hand brakes were applied by the engineer when he "tied up" the train for the night. He seems to have done the correct things before he left the train, but there appears to have been a lack of communication between the fire dept and the dispatcher concerning shutting off the diesel engine and the dispatcher for not contacting the engineer about the fire.
One thing I have not seen in the various photos are the locomotives. One article said there were 5. Was there a coupler failure or release and the locos were left at the top of the hill; or are they buried under the debris?
One other note: In a photo, I saw the end of a tank car indicating 30,000 gallon capacity. Assuming the cars were filled to volume capacity, that is 2,190,000 gallons of crude oil on that train.
George In Midcoast Maine, 'bout halfway up the Rockland branch
I think I saw in an article yesterday that a grade of 1.2% was involved, either where the train started or downhill from there.
The CNN article today gives some insight about handbrakes, etc, though lots of questions remain.
http://www.cnn.com/2013/07/10/world/americas/canada-runaway-train/index.html?hpt=hp_c3
Paul
Modeling HO with a transition era UP bent
Randy,
From what I heard, canadian rules dictate that on an unoccupied train the hand brakes sould be set on 10% of the cars + 2. This train had 73 cars and 10 of them had the hand brake set according to the operator who set them.
the police announced a few hours ago that they are considering criminal negligence or even criminal action. The investigation is going on.
Guy
Modeling CNR in the 50's
Dave,
I'm glad you did all that typing,,,,cause I sure didn't want to..As far as the wreck goes,,there are a lot more issue's going on there,then we all being told....The sad part though,,,are the innocent people who had to pay for it..
Cheers,
Frank
zstripe As far as the brakes go,,I believe you have that reversed,,brakes are applied when pressure is applied,,either that or go to every car and mechanically set them..
As far as the brakes go,,I believe you have that reversed,,brakes are applied when pressure is applied,,either that or go to every car and mechanically set them..
The way air brakes work is that there is a train line the length of the train that is used to both supply air to the system and to provide teh signal to apply or release the brakes.
When the system is charged, air pressure is increased in the train line. The brake valve on each car senses the pressure in the train line and when the pressure increases above the pressure in the air reservoir on the cars, the brake valve diverts air from the train line into the air reservior and vents the air out of the brake cylinders, releasing the brakes.
When the air pressure in the air reservoir equalizes with the train line pressure, the brake valve closes the connection to the brake reservior.
When the brakes are applied, the air pressure in the train line is reduced, when the differential between the air reservoir and the train line reaches a certain level (I think its the reservior 5 psi higher than the train line) , the brake valve moves to vent air from the RESERVOIR into the brake cylinders, applying the brakes. The pressure in the brake cylinder increases and pressure in the reservoir decreases until the pressure in the reservoir equalizes with the train line. The brake valve then moves to hold the pressure in the cylinder and reservoir. If an additional brake application is made, the pressure in the train line drops again, the brake valve senses the train line is lower than the reservoir, it moves and vents pressure from the reservoir to the cylinders, increasing the pressure in the brake cylinders, increasing braking force. When the train line and reservoir equalize, the brake valve moves to a neutral position again, holding pressure in the cylinder and reservoir.
When the brakes are released the pressure is increased in the train line, the brake valve sense the pressure is higher in the train line than the reservoir, the valve moves to charge the reservoir, and vents the brake cylinder to release the brakes.
(Technically the modern systems use the reservoir pressure to increase the train line pressure, releasing the brakes more quickly)
The net is that the pressure in the train line is not directly connected to the brake cylinders, the trainline is connected to the reservoir and the reservoir is connected to the brake cylinder.
The air brake rules in the US prohibit relying on air brakes to hold a standing train. Hand brakes must be applied to hold a "parked" train. Don't know what the Canadian rules require. In the US the engines running or not shouldn't have any impact on whether the cut rolled away, the key to this whole thing is if the required hand brakes were set, were they sufficient and whether any hand brakes were released.
The engines and the air brakes would be a red herring if the Canadian rules are similar to US rules. Talking about them makes good sensational newspaper copy.
Dave H. Painted side goes up. My website : wnbranch.com
I knew I had left some parts of the brake deal when I tried to explain it,,oh well..My recollection of the accident,was that it was on a grade..
Mr,B,
I have been following that myself,,some tragedy,over a simple error,,My understanding however,that there were issues that were also related.. As far as the brakes go,,I believe you have that reversed,,brakes are applied when pressure is applied,,either that or go to every car and mechanically set them..When are Intermodal cars were spotted in our yard,an air line was attached to the end car to keep the brakes applied,so the crane would not move the cars,when they were being,unloaded,or loading.. On a semi,tractor trailer,they had air tanks and they had to keep at least 60 PSI in them otherwise the max-z brakes would go on,,very heavy duty sprung brake chambers,that had to have,at least 60 PSI,to stay released..
Don't know about the fine points of the braking system, but Canadian authorities are now treating this as a criminal case. They believe the train was deliberately "tampered with".
Carl
"I could never belong to any club that would have me as a member."
Bleed out of the train line would apply the brakes - but eventually the reservoir on the cars will bleed out and then there is no more air to force the brake cylinder to hold the brakes tight. It would seem unusual that enough brakes bled out in that time frame to allow the train to move, unless it was on a grade. And one of the real railroaders here can correct me, but I thought the rules required a certain number of hand brakes to be set on the train when left standing unoccupied - or does that not apply if the power is connected and running?
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I'm sure most of us have been following this. Good wishes and condolences for those who lost loved ones and friends in the fire.
I've got a question about the braking system, which seems to be the focus of speculation at the moment. It seems that the train was secured and left for the night with the engine idling. At some time, there was a small fire onboard, which was quickly extinguished. The fire department may have shut down the engine.
But, what would happen to the brakes? My understanding of the Westinghouse air brake is that the brakes are applied when pressure is released, so a failure of the system, or a slow bleed-out of pressure once the engine is shut down, should activate the brakes. Is this correct?
It takes an iron man to play with a toy iron horse.