mook Wrote:
-------------------------------------------------------
> Something in a PBS broadcast tonight, followed by
> this item in Reuters (
> [
www.reuters.com]
> rain-derailment-safety-exclusive-idUSKBN0NY2DW2015
> 0513 ) suggests a way that the overspeed could
> happen. Apparently, the Amtrak NEC flavor of PTC
> (ACSES is the acronym, I think) wasn't installed
> on that section of track (yet). I thought it was
> active throughout the NEC, at least where Amtrak
> owns the tracks - apparently not.
>
> Explains one thing I didn't understand - how on
> the NEC line you could carry that much speed so
> close to a restriction. With a clear signal and no
> externally enforced speed restriction absent the
> overlay system, the engineer may have recognized
> the curve and dumped the air too late.
>
> NTSB did say in a press conference that the speed
> peaked at 106 mph, dropping to 102 in a couple of
> seconds after emergency braking started. Then
> their data stopped.
Other trains have been able to successfully comply with the speed restriction.