The Power of Wind: Can winds actually cause a freight train to derail?
Wednesday, October 8, 2014, 5:10 PM - With Tuesday's CN train derailment outside of Clair, Saskatchewan, strong winds were reported in the area, possibly playing a role in the accident. So, how do winds have such a big impact on such a large object like a freight train?
The exact cause of Tuesday's train derailment outside of Clair, Saskatchewan has yet to be determined, and the potentially toxic smoke blowing from the area is the major concern at the moment. However, this incident follows less than six weeks after another derailment, near Waldeck, SK, west of Regina on August 28. In that case, Canada Pacific Rail blamed what they called plow winds, a somewhat outdated term for powerful straight-line winds that flow out from a thunderstorm. These are now more commonly known as a derecho.
According to Environment Canada, there were thunderstorms in the Waldeck area on August 28, and nearby Swift Current recorded sustained winds of around 20-30 km/h the evening of August 28, but the station also logged a maximum wind gust of 70 km/h. In that kind of gale-force wind, a person could easily lean over in the direction of the wind and not fall over, and it's strong enough to make it nearly impossible for a person to walk into the wind.
Still, your average box car from a freight train, even if it's empty, represents 20-30 tons worth of steel. That's a lot bigger than your average person, especially when you string 30 of them together and add an even heavier locomotive to the front (and possibly back as well). The train's weight certainly would help it stay on the tracks, but 30+ rail cars represent a lot of surface area to push against, especially when the blasts of wind can potentially affect the entire length of the train all at once.
In the case of the August 28 derailment, wind direction was apparently a big factor as well. With the winds blowing roughly from north to south, and the train tracks running east to west, the winds would exert the maximum amount of force against the north sides of the box cars. If the strong winds were already blowing against the side of the train to start, and then a gale-force wind from a storm-outflow derecho struck the side of the train as well, it could easily have destabilized the entire line and spilled it off the tracks.
That wasn't the only train derailment blamed on these straight-line winds. NOAA scientists have examined several similar incidences, with ones in Kansas in May 2014, Texas in 2013, and North Dakota in 2006, just as a few examples. Strong winds - from 60-80 miles per hour - with sudden changes in wind direction, played a major role.
Could winds truly be a factor in this incident? According to Weather Network meteorologist Brian Dillon there were strong winds in the area at the time - sustained winds around 35 km/h and gusts up to 50 km/h. Those winds were apparently blowing a bit more in-line with the direction of the tracks (rather than directly across them) so they wouldn't be exerting quite as much force on the train, compared to what happened near Waldeck. Based on weather radar plots, though, there were storms nearby, generally to the northeast of the area. However, whether they were close enough to cause a significant derecho to flow across the tracks is unknown.