Train - hazardous cargo "accident"

[PILOON]

I gather that they relied on a running engine to keep pressure on the air brakes. With that engine down (due to the reported fire) I have to believe that numerous minor air leaks at couplings and aged cracked hoses would have allowed pressure to drop off fairly rapidly. Gravity would have done the rest.
The mechanical brakes on each car are, I believe, for individual yard parking and not for a complete train. Even were there an accumulator on line that would have bled away in a short time.

No matter what rules and regs that were followed, my thoughts are that it is darn close to criminal to leave such a monster of potential mass destruction unattended (and I understand) unlocked.

 

[Rustyiron]

It wasnt just the external Estop that was activated, but the internal ones were too.

Now bear in mind its from the railroad, but was there Sabotage? Or perhaps negligence (not intentional) on the part of the fire fighters who were there earlier fighting a small fire on the train???

A few weeks ago a bunch of idiots were on the tracks of that line here in Maine, with their signs & stuff waiting to protest the train. The train never showed up and I think a few were arrested. Makes you wonder how far they would go? They protest pipelines also. I'd bet big money that they all DROVE there to the protest. According to the local TV news tonight the oil tanks on that line have increased a bunch in the last 10 years. I can't quote the figures she gave as she gave 2 different numbers (typical) of the gals. shipped today are either 1.6 or 5.? millions annually (2011)

 

[Leyenda30]

There should have been a locked derail on the down grade end of the track if it were a siding or a temperary derailer if left on the main line. The air hose between cars when fully charged releases the brakes. When air pressure drops the brakes apply....when the hose is broken the train stops in emergency. Usually 1 car in 10 has a hand brake applied when left standing and more on a heavily loaded train. It appears to me someone released the brakes with the bleed valve or something was involved in the fire previously caused the brakes to be pumped off inadvertently but the handbrakes should have held. So I feel it was tampered with either by juveniles or others. Retired 30 year railroader...hope this helps. JP

 

[Scooby074]

A few weeks ago a bunch of idiots were on the tracks of that line here in Maine, with their signs & stuff waiting to protest the train. The train never showed up and I think a few were arrested. Makes you wonder how far they would go? They protest pipelines also. I'd bet big money that they all DROVE there to the protest. According to the local TV news tonight the oil tanks on that line have increased a bunch in the last 10 years. I can't quote the figures she gave as she gave 2 different numbers (typical) of the gals. shipped today are either 1.6 or 5.? millions annually (2011)

Yes environmentalists (and NIMBYs) are some of the biggest hypocrites out there. Crude by train volume has increased by a HUGE amount in the last few years. Pipelines while not 100% are safer than trains. Crude has to move SOMEHOW... perhaps we should all go back to horse and buggy?:confused2:

 

[Scooby074]

There should have been a locked derail on the down grade end of the track if it were a siding or a temperary derailer if left on the main line. The air hose between cars when fully charged releases the brakes. When air pressure drops the brakes apply....when the hose is broken the train stops in emergency. Usually 1 car in 10 has a hand brake applied when left standing and more on a heavily loaded train. It appears to me someone released the brakes with the bleed valve or something was involved in the fire previously caused the brakes to be pumped off inadvertently but the handbrakes should have held. So I feel it was tampered with either by juveniles or others. Retired 30 year railroader...hope this helps. JP

Spring applied makes sense to me! So what about the story that the engine was kept running in order to have air to keep the brakes on?

Is a derailer standard protocol?

 

[tcartwri]

Read the scenario in Quiz #2 near the end of this article. Is this feasable, considering the events leading up to the runaway?

North American Freight Train Brakes

 

[Leyenda30]

Spring applied works on a tractor trailer not rail cars. Most times all engines are shut down to conserve fuel if the temp is above 40 degrees. Usually when tied down with hand brakes the air is dumped to apply emergency brakes on all cars. The brakes can be released by a bleed valve which is used in switching where the cars can be shoved and continue rolling by gravity in a yard as in a hump yard where cars are sorted in large numbers. Derails are the endustry standard. JP

 

[Scooby074]

Ok.. I know truck brakes... but Ive given myself a crash course in train brakes through Tim's link above.

So if I understand, a drop in air pipe pressure will cause the air in the boxcar reservoirs to apply the brakes on that individual car and the remaining cars if they meet the threshold to shift the triple valve.

If all air is dumped in the air pipe (ie: emergency), the brakes are applied by the individual car reservoirs via the triple valve.

The brakes are spring returned (un-applied) if there is enough air pipe pressure to shift the triple valve on the car which vents the brake application cylinder allowing the spring to unlock the brakes and causes the car reservoir to begin to recharge.

Is that a VERY rough approximation of how a train braking system works?

 

[Leyenda30]

Is that a VERY rough approximation of how a train braking system works?[/QUOTE]

Yes that's pretty much it. The brakes start applying from the front of train to rear and even braking occurs once the pressure equalizes in all the cars and release in the same order. It's possible that the conductor may have forgotten to do his duty but unlikely.

 

[Cub 7274]

The terrible part is that this "shortline" runs a 1 man crew so the engineman only system does not require them to apply handbrakes to a train left for recrew.
They "set" the airbrakes and apply a handbrake to the "lead" locomotive which is not even locked.
If the fire shut the lead locomotive down or the fire crew was in the cab and hit the brake handle the brakes could release and 1 handbrake on the unit would never hold the train after the air bled off the trainline not good