From: ahk@chinet.com

John Albert  wrote:
>On 11/1/16 7:43 PM, hancock4@bbs.cpcn.com wrote:

>>I would think if it had been in place, it would've prevented the
>>recent Metro North and Amtrak NEC accidents were excessive speed
>>was the cause.

>You would be wrong, because at both locations where the
>above wrecks occurred, there ALREADY WERE cab signals
>suppliemented with speed control, and those systems have
>been in place for years.

>Cab signals and speed control (until the Metro-North
>accident) applied ONLY to signal indications (i.e., would
>apply brakes if engineman did not take appropriate action
>after passing a more restrictive signal indication).

>After the Spyten Duyvil wreck, Metro-North installed cab
>signal "drops" approaching certain speed restrictions. These
>operate independently of signal indications.

>The Amtrak Frankford Junction wreck was also a "slowdown"
>NOT associated with signal indication, and again, the
>existing cab signal/speed control system did not enforce it.

. . . but the speed restriction was enforced in the other direction.

>ACSES -- which DOES enforce ALL timetable speeds and
>slowdowns, WOULD HAVE prevented it, but ACSES wasn't in
>service yet at that particular location.

What infuriates me about this discussion, every time it comes up
in the media, is how decades-old mature signalling and control
technology gets lambasted. It was quite capable of enforcing
speed restrictions IF INSTALLED, but for whatever reason, they
guessed during the NECTIP that this wasn't a location that
needed the enforcement.

A similar observation can be made about ACSES: If its database of
operations profile and timetables elements are wrong or missing or
something didn't get updated yet, well, it won't be able to enforce
a speed restriction it doesn't know about.

None of this precludes the engineer from learning and obeying
the timetable. We need to continue to think of signal and control
systems as being available to complement the information the
engineer should have available. We're not at the point at which
it does everything a skilled and careful engineer does, and we
may never be at that point.

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