My theory on why our derailment happened. Plus an
explanation of how a rail car negotiates a curve and what can happen if the
car truck set doesn't swivel (steers) through a curve like it was designed to do.
If my theory is correct then this would be classified as a wheel climb derailment.
It has also been called flange climb. A worn out flange and a lot of curve wear
on the rail can be contributing factors, but the rail in this case had negligible wear
on the inside of the rail head and the flanges on the leading wheel set also exhibited
wear within the permissible range.
The angle the front wheel on the truck set encounters the rail in a curve is called
the yaw angle. In the video I said that car wheels can come off when track gage
is 59 inches, my error, I meant 59 1/2 inches. On Class 2 track like we have the maximum allowed gage by Fed. law is 57 3/4 inches. The gage on the track immediately before the spikes started pulling was 56 3/4 inches, well within specs of where it should be.
Typical track gage is 56 1/2 inches.
Code Fed Regulations also states that on Class 2 track on curves over 2 degrees
the minimum number of good cross ties is 9 per 39 foot rail section. When the RR contractor rebuilt the part where the rails started pulling spikes, they only
replaced 4 ties within 2 rail sections, they deemed that all the other ties met
CFR regulations. There are typically 21 ties per 39 foot section. With that said,
only replacing 4 out of 42 ties, there is no way that bad ties caused the
derailment. Also the tie gang had went thru this entire section 3 1/2 years ago.
Curve 18 is on a very slight down grade. The lead loco was in throttle run 5, the rear DPU
was in 3. The operator just was taking the throttle off both locos when it went
into emergency. Both locos are EMD SD 38-2 rated at 2,000 HP.
If my theory as stated in the video is correct, the rear DPU pushing the last cars
certainly did not help matters and may very well have been a contributing factor,
but I don't believe the cause. We have been running this push pull system since 1999.
This is the first time an event has happened like this on this curve or any other
sharp degree curve, so I highly doubt that the rear unit pushing actually caused
the derailment, but again, with a bad truck set it very well could have exacerbated
the derailment.
Sorry, derailment happened on Wednesday, not Thursday as I said in the video.
Next video coming up will be on what damage happened to the locomotive.
I've got many more videos coming up on the track repair work that occurred
so stay tuned and thank you very much for watching, it is appreciated!
See the first vid about the derailment on my channel, I am
also making a playlist there of all the derailment videos I will be soon posting
for you.
https://www.youtube.com/channel/UCTWNOX8VRkBtevxsPpC3cBA
On the Community Tab on my channel I will be posting many still pictures
of the events if you would like to view them.