Apearantly the diesel #21 was coupled ahead of steamer #12. Given the very short wheel base of #21 in compareson to it's length combined with the higher lateral forces that would be applied to it by the pilot of #12 going around curves as opposed to having been coupled between the tender and trailing cars, it is quite possible that it was a factor in the derailment.
As to the FRA, here in Fort Collins, our streetcar line has been inspected several times by the FRA and they have found no problems. We have also had an exemplary safety record. The Fort Collins Municipal Railway is considered non-insular due to our 17 public grade crossings. One other thing about the FRA is that they specifically exclude railroads with gauges less than 24 inches from their control.
Roger Mitchell
Master Mechanic
Fort Collins Municipal Railway