From: j.albert@snet.net   
      
   On 7/11/14 7:41 PM, Adam H. Kerman wrote:   
   > Damn. You're suggesting it could be sabotage.   
      
   No, not "sabotage" at all.   
      
   I'm suggesting that the automatic brake valve in the engine   
   (which almost certainly had been placed into the application   
   zone by the engineman) somehow got bumped or placed back to   
   the "release" position. It may have been by accident, and   
   perhaps the person who moved the handle didn't even realize   
   the implications of changing its position.   
      
   The train was probably tied down with a substantial service   
   applicaton of the brakes, perhaps a 15-20lb reduction, maybe   
   even "full service" (26lbs on a 90lb brake pipe). This would   
   be readily observable on the event recorder printout on each   
   engine.   
      
   Let's consider that the engine consist was dead, no longer   
   supplying air to the main reservoirs on the engines. What   
   happens in that case?   
      
   Normally, with MR pressure normal, the automatic brake valve   
   in "service position" will maintain the brake pipe pressure   
   (pressure maintaining feature) so that the brake pipe   
   reduction "holds steady". A 20lb reduction would remain "a   
   20lb reduction" for as long as the brake valve remained   
   untouched.   
      
   But -- what would happen if the brake pipe pressure began to   
   leak down (after the engines died)?   
      
   As brake pipe pressure lowers, brake cylinder pressure   
   INCREASES, up to the point of "equalization" (full service).   
   If the brake pipe continues to leak down (all the way to   
   zero), this in itself cannot release the brake application   
   on the cars. The control valves on the cars will only move   
   to the release position if brake pipe pressure -increases-.   
      
   Now, let's deal with the issue that "the car brakes could   
   leak off".   
      
   I believe those type of tank cars have a control valve   
   mounted on one end of the car, but have truck-mounted brake   
   cylinders. I can't speculate as to whether the truck-mounted   
   cylinders are more prone to leakage than a single large   
   brake cylinder on, say, a boxcar. But I sense that they are   
   designed to "hold" cylinder pressure for a certain amount of   
   time with minimal leakage. Otherwise, descending long grades   
   (where cylinder pressure must be maintained for a while)   
   would be problematic.   
      
    From what I read, roughly an hour transpired between the   
   time the lead (only running) locomotive was shutdown, and   
   the train moved. I don't believe enough brake cylinders on   
   enough cars could have leaked off their pressure within that   
   time frame to degrade the application to the point where the   
   train would roll. Even if 10% of the cars had bled down,   
   that would still have left 60+ cars with substantial brake   
   pressure to hold the rest.   
      
   Also worth mentioning is I don't believe a car cylinder's   
   leaking down by itself will cause the control valve on that   
   car to move to the release position. The control valve   
   should remain in the service position, even if the cylinder   
   pressure has leaked away. Why could this be important?   
   Because (if I remember my air brake correctly) when an ABDW   
   control valve moves to the release position, it uses a   
   portion of the air stored in the emergency area of the car   
   reservoir to "propogate" the release to other cars "down the   
   line" (this is called the "accelerated release feature").   
   But that only happens when an increase in brake pipe   
   pressure causes the control valve to move from application   
   to release.   
      
   So, what does this all mean?   
      
   1. The loss of brake pipe pressure would not release the   
   brake application on the train   
   and   
   2. Individual "leak offs" of cars in the train would not   
   cause a release of the brake application, either.   
      
   What -might have- caused that release?   
      
   The brake pipe pressure would have to INCREASE.   
   The only way that this will happen is if the automatic brake   
   valve on the engine is placed back into the release position.   
      
   There were several individual freight car brakes applied.   
   (know that)   
   There may have been locomotive hand brakes applied. (don't   
   know that)   
   And there were certainly air brakes applied on the locomotives.   
      
   So how did events transpire?   
   My theory:   
      
   Engineman stopped train with air, perhaps increased   
   application to full service.   
   Engineman left locomotive independent brake applied.   
   Engineman applied car brakes, probably applied locomotive   
   hand brakes as well.   
   Engineman leaves train believing it to be secure.   
      
   Engine catches fire.   
   At this point I'm not sure who arrived on the scene first.   
   Might have been fire personnel, perhaps the other RR   
   employees (not T&E).   
      
   Normally, a locomotive main reservoir is charged to 125-140lbs.   
   Depending on the particular engine, locomotive brake   
   cylinder pressure is either 45lbs (two brake shoes per   
   wheel) or [roughly] 72-78lbs (one brake shoe per wheel).   
   What this means is, even if the engine dies, there remains a   
   "residual amount" of air in the main reservoirs for a while,   
   which slowly begins to deplete. Kill the engine, and the   
   brakes will still "hold" for a while before MR pressure   
   drops below 80lbs and the engine brakes begin to weaken.   
      
   If the automatic brake handle had remained in the   
   application position, the train application would have   
   "held" and the train would not move, even with the loss of   
   engine brake cylinder pressure. Not in the time span involved.   
      
   BUT -- if the train brakes had been released -- even an   
   "unintentional" or accidental release -- the entire scenario   
   changes.   
      
   The combination of full brake cylinder pressure on the   
   locomotives + several car hand brakes probably were enough   
   to keep the train from moving (if I recall, the train was   
   stopped at a location where there may have been a slight   
   downgrade, increasing where the engines were standing).   
      
   But what if the engines are dead, and MR pressure begins   
   decreasing?   
      
   At some point, the loss of brake cylinder pressure on the   
   locomotive consist will produce a condition where there no   
   longer remains "enough brake" to hold the train, and it will   
   begin to move. We know what happened next.   
      
   But again, assuming that the engineman did what [I believe]   
   any other engineman would do (i.e., leave the train with a   
   solid air brake application applied), I can't see how the   
   train could move within the time frame of an hour, even with   
   the loss of locomotive brake cylinder pressure.... unless....   
   .... somehow, that automatic application got released (at   
   the brake valve).   
      
   Even with the engines dead, MR pressure would be present   
   (but declining) for a while. I believe with a full service   
   application (90lb brake pipe), it would take around 66-67lbs   
   in the brake pipe to cause the control valves to move to   
   release. Thus, even with the engines dead, it was still   
   possible to release the train brakes (for a short time, at   
   least). We're not talking "hours" here.   
      
   This isn't rocket science.   
   The locomotive event recorders record brake pipe pressure   
   and locomotive brake cylinder pressure.   
   I'm not sure if the event recorders on these engines   
   monitored the actual physical position of the brake valve. I   
   will guess not, that they only record air pressures on older   
   #26 equipment. But that would be enough.   
      
   Those reading the printouts (or perhaps a screen display) of   
   the event recorders would have checked these pressures first.   
   If they did, they probably knew right away "why the train   
   moved".   
      
   But -- again -- the data on those recorders probably reveals   
   "an event" that "doesn't support the narrative" -- that   
   "narrative" being that "it was the engineman's fault". I   
   believe SOMETHING ELSE occurred in the cab AFTER he departed   
   the scene that became the critical "key" to the disaster   
   (and not just the fact that the engine caught fire and was   
   shut down).   
      
   I believe the TSB investigators know what that event was,   
   but don't know how to handle it for public consumption. They   
   are keeping it "under wraps" for the moment, because to   
   reveal it might turn the entire scenario of the disaster   
   cross-lots.   
      
   Sorry for the long post.   
   But that's the way I see it, and that's the way I'm callin' it.   
      
   I could be wrong.   
   But this report should have been out months ago.   
   What's holding it up?   
      
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