Go back and read previous discussion thread: http://www.altamontpress.com/discussion/read.php?1,183698,183698#msg-183698

Information so far says runaway was operating as 1+1+1 (3 locos, lead, mid-train DPU and rear DPU). Simple railroad physics: Engines at about 210 tons each. Nominal adhesion level on good rail = 30%. 210 x 2,00 = 420,000 engine weight x 30% adhesion = 126,000 pounds retarding force x 3 engines = 378,000 pounds maximum theoretical retarding force from engines.

112 cars at 140 tons each (my estimate) = 15,680 tons + engines (3 x 210) = 16,310 tons total estimated train weight. Force of gravity is 20 pounds per ton per percent of grade, and reports are grade is 2.2% which is very common maximum heavy grade in North America. 2.2% x 20 pounds x 16,310 tons = 717,640 pounds of force on grade due to gravity (no corrections for friction). At a maximum of 126,000 pounds retarding force per engine, you would need a minimum of minimum engines to even stand a remote chance of holding the train on the grade with just the engines, but realistically it will take more than that considering the temperature was below zero and friction brakes don't work so good nor do you have high adhesion levels.

GE rates a six motor AC loco at 98,000 pounds dynamic braking, so three locos would be 294,000 pounds maximum retarding force trying to counteract 717,000+ pounds of force from gravity, so supplying less than a third of the needed retarding force. The air brakes have to be depended upon to control and stop the train, especially considering that dynamic brakes are inherently not a fail safe system.

Transport Canada has issued an emergency handbrake rule, which CN, CP and the Canadian rail organization are appealing. http://www.tc.gc.ca/eng/railsafety/ministerial-order-19-03.html

So on a 2.2% grade with 15,680 trailing tons, you are now required to apply a minimum of 98 handbrakes of the 112 cars (or 87.5%). I think this is overkill/over-reaction, because I think somewhere around 60% of brakes should hold it (a few more in cold weather). Some Canadian grain cars I've seen have a pulley on the handbrake chain, so it does take longer to apply the handbrakes. So lets say you are in good shape and are really hustling, and you can apply one handbrake every two minutes - it will take you 176 minutes (3 hours) to tie down your train. At night, poor weather and/or deep snow (or if like me you aren't in the best of shape), it will take much longer. Even using my 60% estimate, you are looking at a minimum of 67 cars so over two hours to tie down handbrakes.

The issue here, and in the previous runaway several years ago where the PCS wasn't reset knocking out the dynamics, you don't have enough holding force from the engines to release the brakes and remain stopped while recharging the train brake system. Long standing rules have required enough handbrakes to be applied to release and recharge, then make a sufficient air brake application to hold the train, and then release the handbrakes before starting down the grade. A wild guess would be that between the engine brakes and handbrakes, you would still need to tie down a third of your train to release and recharge. So tie down 38 brakes or more (over an hour?), release and recharge the air brake system, release the handbrakes (another hour) and hopefully safely continue.

What I am thinking is that the theoretical ability to run a train in the most economical manner possible (huge trains with small crews) is now exceeding the technology and employee capacity to safely control a train in a consistent manner and deal with any less than ideal circumstances.

It wasn't that many years ago that a train of 55 loads on a heavy grade was considered a "big" train. This was only 7,200 tons, and if you had 3 SD40-2s on the lead and another 4 in the middle you would have 21,000 hp and 400,000 pounds of potential dynamic braking effort. And don't forget you had the head end brakeman plus the conductor and flagman in the caboose to tie down the train.