Hi cascade and Everybody
Cascade, we now know that it was a failing piston cylinder in the engine of the power car that had caused both fires on this consist that day. Therefore the firefighters would have had no option but to shut down the engine as to do anything else would have seen the fire reignite yet again plus they would have been under standing orders to do so. However, shutting down the engine should only have lost the air pressure in the train line due to the innumerable leaks in the system. This should have left the air reservoirs on the freight cars still fully charged by the system of non-return valves on the air tanks themselves which stops their fully charged pressure going back into the airlines.
As I have stated earlier in this thread I only have experience of air brakes as used in the road haulage industry. From that experience I have always found there is no way from the cab of a vehicle that you can discharge the air tanks on the trailer and it is these air tanks which are the second system and apply the brakes. The air tanks for that system can only be discharged manually by releasing the drain valves on the tanks themselves, and on the more modern systems you need a spanner/wrench to do that. Air brakes are designed that if a compressor fails and the pressure drops in the airlines or train line as in this case, the brakes are then applied and will remain applied until the airline pressure is regained. I suspect that the braking system on this train was so poorly maintained that the non-return valves did not operate when the engine was shut down and allowed the second system which applies the brakes to also fail. If that is the case, those responsible should face corporate manslaughter charges for gross negligence and nothing short of that.
Cascade, if there is a way of discharging the freight cars air reservoirs from the power car could you please describe how that could be done as I would very much like to know. I believe also that there were three or five power cars in this consists. If the others were left running why did the pressure in the train line drop as their compressors should surely have created enough pressure to maintain the system, or was the entire brake system so poor and leaking so badly that it took all the power cars to be running just to maintain the pressure even when the train was stopped.
Bill
Yes it is a fail safe ... but any number of things can accidentally or intentionally disable the fail safe braking operation (which I can't go into how to do so).
With proper settings the air brakes operate (flawlessly, 99.9% of the time), in this case something went horribly wrong, and the generator/compressor was intentionally shut off, by this, and other fiddling with controls, and valves, disabled the emergency braking, allowing all air to escape from both the trainline and all resivoirs, and the emergency brake release reservoirs. Like I said ... there are two presurized systems on a train, one applies the brakes when it loses pressure, by triggering the other pressurized system which pushes out on the brake pistons, if that 2nd pressurized system is also depleted, the emergency brakes pistons release, and you have an uncharged air brake system, a non-presurized runaway train of Radio Flyer wagons rolling downhill.
Cascade, we now know that it was a failing piston cylinder in the engine of the power car that had caused both fires on this consist that day. Therefore the firefighters would have had no option but to shut down the engine as to do anything else would have seen the fire reignite yet again plus they would have been under standing orders to do so. However, shutting down the engine should only have lost the air pressure in the train line due to the innumerable leaks in the system. This should have left the air reservoirs on the freight cars still fully charged by the system of non-return valves on the air tanks themselves which stops their fully charged pressure going back into the airlines.
As I have stated earlier in this thread I only have experience of air brakes as used in the road haulage industry. From that experience I have always found there is no way from the cab of a vehicle that you can discharge the air tanks on the trailer and it is these air tanks which are the second system and apply the brakes. The air tanks for that system can only be discharged manually by releasing the drain valves on the tanks themselves, and on the more modern systems you need a spanner/wrench to do that. Air brakes are designed that if a compressor fails and the pressure drops in the airlines or train line as in this case, the brakes are then applied and will remain applied until the airline pressure is regained. I suspect that the braking system on this train was so poorly maintained that the non-return valves did not operate when the engine was shut down and allowed the second system which applies the brakes to also fail. If that is the case, those responsible should face corporate manslaughter charges for gross negligence and nothing short of that.
Cascade, if there is a way of discharging the freight cars air reservoirs from the power car could you please describe how that could be done as I would very much like to know. I believe also that there were three or five power cars in this consists. If the others were left running why did the pressure in the train line drop as their compressors should surely have created enough pressure to maintain the system, or was the entire brake system so poor and leaking so badly that it took all the power cars to be running just to maintain the pressure even when the train was stopped.
Bill
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