From: j.albert@snet.net   
      
   I downloaded the pdf format of the Lac Megantic report.   
      
   It goes on for around 191 pages (in pdf format), but most of   
   it is irrelevant as to answering the question, "why did the   
   train move?"   
      
   That answer can be found on page 23, in Table 1, "Locomotive   
   event recorder information".   
      
   Evidently, the engineman made a grave mistake in leaving his   
   train the way he did. This mistake may not have been an   
   intentional, but if he had done ONE MORE THING -- even   
   though the number of hand brakes was insufficient to hold   
   the train -- the train would not have moved within the time   
   frame it did, even though there was no longer  enough (or   
   any) locomotive air pressure to keep the locomotive   
   independent brakes applied.   
      
   I will offer an explanation:   
      
   Let's look closely at the FIRST TWO events in the event   
   recorder timeline (p.23):   
   1. Brake pipe pressure is reduced to 82lbs to stop the train   
   at Nantes using a service application.   
   (Note: I believe at this point, the engineman applied some   
   locomotive hand brakes, and car hand brakes, and then....   
   2. Brake pipe pressure increases to 94lbs -- train brakes   
   are released.   
   (Note: the engineman did this to [ostensibly] test the   
   effectiveness of the engine brakes and train hand brakes   
   with train air brakes released).   
      
   The following is excerpted from the report, pages 1 and 2:   
   [[ At around 2250, the train arrived at Nantes, was brought   
   to a stop using the automatic brakes, and was parked for the   
   night on a descending grade on the main track. The LE   
   applied the independent brakes to the locomotive consist. He   
   then began to apply the hand brakes on the locomotive   
   consist and the buffer car (7 cars in total), and shut down   
   the 4 trailing locomotives. Subsequently, the LE released   
   the automatic brakes and conducted a hand brake   
   effectiveness test without releasing the locomotive   
   independent brakes. The LE then contacted the rail traffic   
   controller (RTC) responsible for train movements between   
   Farnham and Megantic Station (Megantic), who was located in   
   MMA’s yard office in Farnham, to indicate that the train was   
   secured.   
   ...   
   A taxi was called to transport the LE to a local hotel. ]]   
      
   Critical factor that caused the disaster:   
   AFTER CONDUCTING THE "RELEASE TEST" (even though it was not   
   properly tested), THE ENGINEMAN LEFT THE AUTOMATIC AIR BRAKE   
   (TRAIN AIR BRAKES) IN THE "RELEASE" POSITION.   
   HE NEVER RE-APPLIED THE TRAIN AIR BRAKES USING THE AUTOMATIC   
   BRAKE VALVE BEFORE HE LEFT THE TRAIN.   
   (I will delve more into this below)   
      
   What happened next (after lead locomotive had been shut down):   
   Refer to page 23 again, and look at event 4:   
   "Brake pipe pressure began to decrease, and continued to   
   decrease at an average rate of 1psi per minute"   
      
   Since there was no longer enough air supplied from the   
   locomotive to replenish and maintain brake pipe pressure, it   
   began to slowly "leak away".   
      
   HOWEVER -- and this is VERY important -- the leak was "slow   
   enough" so that the control valves on the cars did not move   
   to the service position, which would re-apply brake cylinder   
   pressure on the cars.   
      
   How could this be?   
   Because one of the first things I learned in air brake as an   
   engineman was that a "service rate of reduction" is a   
   movement of air in the brake pipe equivalent to 550 feet per   
   second. (aside: emergency is a reduction rate of about 930   
   fps). The air pressure was reducing in the brake pipe, but   
   at a slow rate, not sufficient to trigger the car control   
   valves to move to the application position.   
      
   The end result is that the brake pipe pressure slowly   
   declined to the point where neither a service application OR   
   an emergency application was possible -- in effect, the cars   
   were sitting there with air pressure still in their main   
   reservoirs, but it couldn't be directed to the brake   
   cylinders because the control valves could no longer respond   
   to the brake pipe.   
      
   That's why the train "moved" -- because the train was left   
   with the car air brakes released, and the   
   slowly-leaking-down brake pipe effectively disabled any   
   chance that they could re-apply.   
      
   That's just about the end of the story. That's why the train   
   actually began to move. What additional action might have   
   changed this?   
      
   Let's consider -- what if (before leaving), the engineman   
   had RE-APPLIED the automatic brake valve to a 20lb   
   reduction, leaving the train with the air brakes applied on   
   the cars and the brake pipe at approximately 74lbs ??   
      
   With the car control valves in the service position (and   
   brake pipe at 74lbs), they would have REMAINED in the   
   service position even as the brake pipe pressure began to   
   drop away (after the engine failed and MR pressure was   
   depleted). The control valves won't move to the "release"   
   position unless there is an INCREASE in BP pressure of about   
   1.5-2.0 lbs. But with dead engines, that wouldn't have happened.   
      
   The result would be that the brake pipe pressure might drop   
   right down to 0, but the air brakes on the cars would have   
   remained applied. A few cars might have had cylinder   
   pressure "leak off", but even this would not change the   
   position of the control valves (applied).   
   There would have remained enough restraining force on the   
   train to hold it still.   
      
   But this didn't happen -- again, because once the engineman   
   released the automatic air brakes, he never re-applied them   
   before leaving the scene.   
      
   The question is:   
   Why didn't he re-apply them?   
      
   Only he can answer that question.   
   It may have been an oversight, completely unintentional. He   
   might have been tired, anxious to get to the motel, and   
   simply forgot.   
   But again, a terrible mistake.   
      
   Whenever I left a train standing with the locomotive   
   attached and "live", I always put the service brake valve   
   into the application position. On freight, it was also a   
   good idea to move the brake valve handle to the "handle out"   
   position, then remove the handle (you could do this on #26   
   equipment) and "stow it away". This way, a trespasser   
   couldn't put the brakes into release by moving the handle,   
   because the handle wasn't even there. It was just good practice.   
      
   Again, I can't understand why the engineman didn't re-apply   
   the air, especially since the train was on a downgrade. In a   
   situation like that, you want "all the brakes you have"   
   against the grade -- if not "full service" on the train, at   
   least a good-size reduction in addition to the hand brakes.   
      
   I read a few pages earlier in the report regarding the state   
   of the train air brakes, and how they were to be left with   
   equipment left standing. As presented in the report, this   
   seems ambiguous.   
      
   About the only relevant info I could find regarding leaving   
   a train with the air brakes applied (as well as hand brakes)   
   are here:   
      
   ....a CN rule (p. 22):   
   [[ Trains with locomotives attached with at least 1   
   locomotive running can be left on the main track with only 1   
   locomotive hand brake applied, provided that there is brake   
   continuity throughout the train, the automatic air brakes   
   are fully applied and the independent brakes are applied. ]]   
      
   ....From CN special instructions (also on p. 22):   
   [[ The automatic air brakes must not be solely relied upon   
   to secure equipment against undesired movement. ]]   
   (NOTE that it says "solely relied upon", but that does not   
   exclude the use of the automatic air brake to supplement   
   hand brakes)   
      
   I don't know whether there were any instructions similar to   
   these in MMA operating rules and special instructions.   
      
   I didn't see anything from what I read (and admittedly I   
   didn't read the ENTIRE report) that said that, under MMA   
   operating rules and instructions, a train should be left   
   unattended with BOTH hand AND air brakes applied.   
      
   BUT -- as someone who worked on the railroad for 32 years,   
   it was just a good idea to leave a train standing with air   
   applied, if air was available. Just "one more thing" to   
   protect the train against movement.   
      
   I KNOW the rules say that one should never depend solely   
   upon air brakes to secure a train left standing. You put on   
   hand brakes and used the air brakes, too.   
      
   Those who have read this far may repeat the mantra, "if   
   there had been enough hand brakes the train wouldn't have   
   moved". Of course -- that was known from day one, there was   
   no need for a 191-page report for anybody to understand that.   
      
   Of course there weren't enough hand brakes.   
      
   BUT -- if the engineman had only taken that "one extra step"   
   of re-applying his air brakes after releasing them -- this   
   wouldn't have happened.   
      
   I can't speculate as to whether his failure to do this   
   represents negligence on the engineman's part, because (as   
   above) I didn't see anything that might have required him to   
   leave the train with air brakes as well as hand brakes   
   applied. He may not have been required by the operating   
   rules and instructions to do so. It may have been left to   
   his discretion.   
      
   HOWEVER -- if the engineman had re-applied the air brakes   
   that night, the train wouldn't have moved and there wouldn't   
   have been a disaster.   
      
   That's my take on it, and I'm standing by it.   
      
   --- SoupGate/W32 v1.03   
    * Origin: LiveWire BBS -=*=- UseNet FTN Gateway (1:2320/1)