Idler Car Wrote:
-------------------------------------------------------

> What is a "false flange" and how is it used/intended "to create a derailment"?

I'll add a little to what Dr. Zarloff said.

The theory behind this is to create a controlled derailment at a relatively slow speed. To do this, place the throttle in Idle, move the reverser to the opposite direction of travel, and reopen the throttle to Run 1. The hope is that by doing so, one or more axles of the locomotive consist will stop turning, causing the wheels on those axles to start sliding. As they slide, a flat spot forms where the wheel meets the railhead, and will progressively grow larger and built up a false flange. When this false flange encounters a switch, the wheel should derail. The ensuing derailment will cause the train's momentum to rapidly decrease, stopping the movement. Dig?

As an aside, I've updated the Wikipedia entry about the runaway with some additional information, mostly taken from the NTSB's investigation report (a 200 page .pdf document). Those interested can read (or re-read) it here: [en.wikipedia.org]