Pilawt Wrote:
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> So ... Looking at the photo above, why would a
> (presumably hazardous) "Key" train have a higher
> speed limit than other freight trains??

I don't work for BNSF so just a passing on what I've heard. My understanding is that these signs would designate the outer limits of the maximum speed for key trains through municipalities. There could still be more restrictive speeds (designated by F) within those key train limits. So in this case, a key train entering this permanent speed restriction limit would have to comply with the 30 mph limit until the end of that restriction, then resume to no more than 35 until either a lower speed restriction is reached, or the end of the municipal key train limit is cleared.