I gave my opinion on the gulf oil spill right after I heard about it and I was 100% correct within 24 hours of the event. Now, I am going to give my opinion on the train crash in Dupont, Washington.
Here goes. How about little history first? When I was in engineering college over 50 years ago, the one area where all engineering science brakes down is "compressive failure". Column compression failures are called "indeterminate" because there is no way to exactly predict compressive failures. For those of you who are not engineers, think of the problem this way. If you had a 1/4" wood dowel 48" long made from Maple, how much force could it handle as a column before it collapsed? If you tested 100 dowels, you would find some that failed with 20# and some that could handle 50#. Why is that? Some have slight bows while others are perfectly straight. The ones that have bows fail with a lot less load than a perfectly straight one. Now onto the train crash.
First a few facts. The rating for the curve was 79 mph while the train was going 81.1 mph. I have no idea what the safety factor was or how they tested the tracks in the first place. My guess is that they ran a train thru the curve and recorded the actual centrifugal force. That was the right thing to do. Here is where the problem cames in. The train had "two" engines, one at the front end and one on the rear. Now, why is this critical? If the engine in the front tried to slow down and gave drag from the front while the engine in the rear still provided "push", it put the train column in "compression". It is the same as the dowel explained above. If the train was on a straight track, the difference in compression would have had little affect, but on the curve the compression has the affect of buckling the train column. I think this is exactly what happened.
It only takes a split second for a train to go from tension like is was being pulled from each end to a column that is in compression. Think about this. If you pull from both ends on a rope is stays straight, but what happens when you pull in on both ends? I think that is what happened with the train. We will not know for a while what caused the crash, but my position is that it was because of the momentary compression caused by the two engines on the curve. Had they done this same thing on a straight section of track nothing bad would have happened. It was not until they came to the curve that all hell seemed to have broken loose.
That is my position. Watch the final report and see how I have done? I was 100% correct on the oil spill. We'll see how I do on this one.
PS--A few years ago I was driving from Grand Junction up to Vail, Colorado and saw several travel trailers crashed off the road "going down hill". They were all on slight curves like Dupont, Wa. What was happening was that the drivers put on their brakes to slow going down hill around the curves. The travel trailers behind them were pushing them (gravity) like the rear engine was pushing the train in Dupont, Wa The push from behind put the whole rig in compression and the system failed just like I have described above. If the trailers had good brakes that prevented the compression I don't think there would have been any crashes. Braking on a straight away is a lot different from braking on a curve while pulling a trailer. Think about it!
PS--New data shows that the speed limit was 30 mph for the curve and they were going 81.1 mph. I have a $99.00 Tom Tom in my car that would ring a bell if I exceeded the speed limit by more than 5 mph. You have to ask if these AmTrack people are competent and should our government be running a rail road?
Here goes. How about little history first? When I was in engineering college over 50 years ago, the one area where all engineering science brakes down is "compressive failure". Column compression failures are called "indeterminate" because there is no way to exactly predict compressive failures. For those of you who are not engineers, think of the problem this way. If you had a 1/4" wood dowel 48" long made from Maple, how much force could it handle as a column before it collapsed? If you tested 100 dowels, you would find some that failed with 20# and some that could handle 50#. Why is that? Some have slight bows while others are perfectly straight. The ones that have bows fail with a lot less load than a perfectly straight one. Now onto the train crash.
First a few facts. The rating for the curve was 79 mph while the train was going 81.1 mph. I have no idea what the safety factor was or how they tested the tracks in the first place. My guess is that they ran a train thru the curve and recorded the actual centrifugal force. That was the right thing to do. Here is where the problem cames in. The train had "two" engines, one at the front end and one on the rear. Now, why is this critical? If the engine in the front tried to slow down and gave drag from the front while the engine in the rear still provided "push", it put the train column in "compression". It is the same as the dowel explained above. If the train was on a straight track, the difference in compression would have had little affect, but on the curve the compression has the affect of buckling the train column. I think this is exactly what happened.
It only takes a split second for a train to go from tension like is was being pulled from each end to a column that is in compression. Think about this. If you pull from both ends on a rope is stays straight, but what happens when you pull in on both ends? I think that is what happened with the train. We will not know for a while what caused the crash, but my position is that it was because of the momentary compression caused by the two engines on the curve. Had they done this same thing on a straight section of track nothing bad would have happened. It was not until they came to the curve that all hell seemed to have broken loose.
That is my position. Watch the final report and see how I have done? I was 100% correct on the oil spill. We'll see how I do on this one.
PS--A few years ago I was driving from Grand Junction up to Vail, Colorado and saw several travel trailers crashed off the road "going down hill". They were all on slight curves like Dupont, Wa. What was happening was that the drivers put on their brakes to slow going down hill around the curves. The travel trailers behind them were pushing them (gravity) like the rear engine was pushing the train in Dupont, Wa The push from behind put the whole rig in compression and the system failed just like I have described above. If the trailers had good brakes that prevented the compression I don't think there would have been any crashes. Braking on a straight away is a lot different from braking on a curve while pulling a trailer. Think about it!
PS--New data shows that the speed limit was 30 mph for the curve and they were going 81.1 mph. I have a $99.00 Tom Tom in my car that would ring a bell if I exceeded the speed limit by more than 5 mph. You have to ask if these AmTrack people are competent and should our government be running a rail road?
