I find it interesting that the article doesn't really mention that regardless of derailment rate, longer trains increase derailment impact. A longer train can,

I find it interesting that the article doesn't really mention that regardless of derailment rate, longer trains increase derailment impact. A longer train can, of course, derail more cars, and when it derails, will strand more cars (since the train's cars still on the rails are temporarily stopped and often can't be moved until the derailment is partially cleaned up). In addition, derailing the 50th car of a 50-car train can only cascade to cars ahead of it; derailing the 50th car in a 100-car train can cascade in both directions. (Stated more generally, the average car in a 100-car train is twice as far from the end of the train than the average car in a 50-car train.) Even if a 100-car train had the same likelihood of derailment as a 50-car train, a 50-car train would, on average, have reduced impact.