3 ms·

I think the other important piece of data you would need to find is average train length over that same period of time. Fewer derailments could have just as muc

I think the other important piece of data you would need to find is average train length over that same period of time. Fewer derailments could have just as much or a larger impact if the train length is growing.

foobarian 5y ago
Right, given same car count and derailment rate, 2x train length could appear as 1/2 the derailments.
- AnimalMuppet 5y ago
  Depends on if the probability of a derailment is K per train mile, or K per car mile. And I suspect that the answer is "some of both". When a car has a mechanical failure that causes a derailment, that kind of derailment is going to be proportional to the number of car miles. Some other causes (misaligned switches, say) will be proportional to the number of train miles.
mediaman 5y ago
I did find a GAO study that said that trains increased in length by 25% since 2008. But the number of derailments dropped by more than 25% during that time, so the probability of a given car being involved in a derailed train still decreased. There's been other coverage of the ironically named "precision scheduling" in the rail industry causing a lot of labor problems, because it makes for nightmarishly unpredictable schedules for workers. They never know when a train is going to leave until it is full, so after working a shift, workers stay in a hotel waiting for a return trip that they won't know about until 90-120 minutes ahead of departure. I am guessing that the claims around increased derailment may actually be about frustration with the work environment.
simulate-me 5y ago
The average length isn’t enough because the likelihood of derailment might be a function of train length. It’s possible shorter trains have gotten safer and monster trains have gotten more dangerous due to their increasing length.

3 ms·

I think the other important piece of data you would need to find is average train length over that same period of time. Fewer derailments could have just as muc

by joshstrange 5y ago

foobarian 5y ago
Right, given same car count and derailment rate, 2x train length could appear as 1/2 the derailments.
- AnimalMuppet 5y ago
  Depends on if the probability of a derailment is K per train mile, or K per car mile. And I suspect that the answer is "some of both". When a car has a mechanical failure that causes a derailment, that kind of derailment is going to be proportional to the number of car miles. Some other causes (misaligned switches, say) will be proportional to the number of train miles.
mediaman 5y ago
I did find a GAO study that said that trains increased in length by 25% since 2008. But the number of derailments dropped by more than 25% during that time, so the probability of a given car being involved in a derailed train still decreased. There's been other coverage of the ironically named "precision scheduling" in the rail industry causing a lot of labor problems, because it makes for nightmarishly unpredictable schedules for workers. They never know when a train is going to leave until it is full, so after working a shift, workers stay in a hotel waiting for a return trip that they won't know about until 90-120 minutes ahead of departure. I am guessing that the claims around increased derailment may actually be about frustration with the work environment.
simulate-me 5y ago
The average length isn’t enough because the likelihood of derailment might be a function of train length. It’s possible shorter trains have gotten safer and monster trains have gotten more dangerous due to their increasing length.