1920 Rural Retreat Wreck Photos/ATC

Fri Nov 19 16:18:02 EST 2004

Since my reply of Nov. 16 using the term Automatic Train Stop, there have
been other replies and comments using the term Automatic Train Control, so I
hope these new comments will clarify matters.

Automatic Train Control is sometimes used loosely as a general term to
include Automatic Train Stop, but there is a specific distinction.

ATC imposes speed limitations on a train, and will initiate a brake
application if the train exceeds the mandated speed.  For example the ATC
placed in service on the Hagerstown District of the N&W's Shenandoah
Division in November 1924 enforced three speeds depending on conditions
(this was later changed to two speeds to be compatible with the ATC that was
placed into service on the Roanoke District of the Shenandoah Division in
December 1926).  The N&W ATC system also included cab signals.

Automatic Train Stop, by contrast, only functions to apply the brakes if a
train's engineer fails to acknowledge a restricting signal by operating an
acknowledging mechanism in the locomotive cab.  There is no speed governing.

These systems can either be continuous or intermittent.

The N&W Shenandoah Division ATC was continuous, meaning that cab signal
indications and speed enforcement could occur at any point, even between the
fixed wayside signals.  This was accomplished by coils on the locomotive
that picked up codes in the rails that corresponded to the mandated speeds.

Other systems were intermittent, meaning that a restricting condition could
be conveyed to the engineer only at certain fixed locations such as at
wayside signals by means of something such as an inductor on the ends of the
ties that would interact with a coil on the locomotive.  One Mail List
comment on this subject mentioned home signals as an example of such a
location, but distant signals and intermediate signals would have to be
included among fixed locations where restrictions are conveyed to the
engineer under the intermittent system.

So, when I referred to Automatic Train Stop on the ACL between Petersburg
and Richmond, used by the N&W's "Cannonball", I was calling on my
recollection that it was an intermittent system, but I may have assumed too
much when I called it an Automatic Train Stop system.  Does anyone know for
certain whether it was/is intermittent or continuous and whether it was/is
ATC or ATS?

PS  For more details on the N&W ATC see "Nuggets from the Archives" and the
included references in the Nov/Dec 2002 issue of  THE ARROW.

Gordon Hamilton

----- Original Message ----- 
From: <nw-mailing-list at nwhs.org>
To: "N&amp;W Mailing List" <nw-mailing-list at nwhs.org>
Sent: Wednesday, November 17, 2004 3:20 PM
Subject: Re: 1920 Rural Retreat Wreck Photos

> Thanks a lot:  Answers three questions for me!  (Yes, it was the
> Cannonball; yes, it ran from Richmond; and why only a few locos were
> assigned to it.)
>
> Pete Groom
> On Nov 16, 2004, at 7:05 AM, nw-mailing-list at nwhs.org wrote:
>
> > Pete,
> >
> > The Cannonball's operated over the ACL between Petersburg and Richmond.
> > Because that line of the ACL was equipped with a type of  automatic
> > train
> > stop not installed anywhere on the N & W, any N & W locomotive
> > operating
> > over that line had to be specially equipped with the ACL automatic
> > train
> > stop mechanism.  To minimize costs, only a limited number of N & W
> > locomotives were so equipped in order to provide the Cannonball
> > service.
> >
> > Published photographs in Prince's and Reid/Lewis' books show the 120
> > and the
> > 122 in the vicinity of Richmond with the Cannonball, so these two
> > locomotives  must have been equipped with automatic train stop.  There
> > may
> > have been another one or two also.
> >
> > Maybe others can confirm this or give more details.
> >
> > Gordon Hamilton
> > ----- Original Message -----
> > From: <nw-mailing-list at nwhs.org>
> > To: "N&amp;W Mailing List" <nw-mailing-list at nwhs.org>
> > Sent: Monday, November 15, 2004 4:38 PM
> > Subject: Re: 1920 Rural Retreat Wreck Photos
> >
> >
> >> Thanks - I should have remembered that none of the K-1s were
> >> streamlined - too lazy to look it up in the books.
> >>
> >> (TAN  However, wasn't there a K2 or K2a that was known for handling
> >> the
> >> Cannonball every day for some years?  (The 120?)  It was kind of a
> >> demo
> >> that steam could have high availability like the diesels, IIRC.
> >>
> >> pete groom
> >> On Nov 14, 2004, at 3:37 PM, nw-mailing-list at nwhs.org wrote:
> >>
> >>> Both were rebuilt to service. 558 was retired and scrapped in June of
> >>> 1952. The 102 was a K1, (100-115) none of the Class K1 were
> >>> streamlined, only K2 (116-1250 and K2a (126-137) were streamlined.
> >>> The
> >>> 102 was retired and scrapped in October 1957.
> >>>
> >>> Ken Miller
> >>> . . .
> >>
> >> ________________________________________
> >> NW-Mailing-List at nwhs.org
> >> http://list.nwhs.org/mailman/options/nw-mailing-list
> >
> >
> > ________________________________________
> > NW-Mailing-List at nwhs.org
> > http://list.nwhs.org/mailman/options/nw-mailing-list
> >
>
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