Railroad Museum of Virginia

[nw-mailing-list at nwhs.org]

Gordon thanks for the history on the AI labels, it solves a mystery for me. 
Cal Reynolds.
----- Original Message ----- 
From: <nw-mailing-list at nwhs.org>
To: "NW Mailing List" <nw-mailing-list at nwhs.org>
Sent: Wednesday, November 01, 2006 11:07 PM
Subject: Re: Railroad Museum of Virginia



> Viewing this caboose brought back memories to me.  If one looks closely to 

> the right of the "NW" one can see a painted-over ACI (Automatic Car 

> Identification) label.  Many of you can remember seeing these colored 

> labels on both sides of equipment in years gone by, or in old photos from 

> that era. In this Sylvania developed system, each stripe was coded in red, 

> blue and/or white.

>

> Reading up from the bottom, the first stripe was a "start" stripe, and the 

> next four stripes represented the reporting marks (0550 as assigned by the 

> AAR for the N & W as best I remember), the next six stripes represented 

> the equipment number (518666 in this case) and the penultimate stripe was 

> a check digit that was a mathematical derivation of all of the other 

> numbers. The last stripe at the top was a "stop" stripe.

>

> The stripes were retroreflective, meaning that they reflected a light from 

> a scanner straight back into the scanner.  Each wayside scanner used a 

> fast vertically rotating (1750 rpm as best I remember) wheel with 

> multi-faceted mirrors on its periphery that reflected a internally 

> generated beam of light to scan the label from bottom to top several times 

> even at high train speeds past the scanner.  The light was reflected back 

> into the scanner where sensors detected the red, blue or white codes and 

> converted these into the reporting marks and equipment number.  This 

> information could be used by a railroad to determine the identification of 

> each piece of equipment in a train.

>

> Although initial tests verified the technical proficiency of the system 

> before it was mandated by the AAR, after about 1-1/4 million cars had been 

> equipped, experience revealed that the read rate in service was less than 

> expected because of dirt buildup on the labels as well as occasional label 

> damage.

>

> I served on an AAR Technical Task Force to see what could be done to 

> improve this optical system.  We considered several possible solutions 

> without sufficient success.

>

> The AAR then formed a Task Force for New Concepts in ACI.  I served on 

> this committee also, and we considered all known systems for equipment 

> identification, finally narrowing the search to a system using microwave 

> scanners to interrogate passive responders on the equipment.  This is the 

> system that was subsequently adopted by the AAR, and is currently in use, 

> having replaced the optical system after tens of millions of dollars had 

> been spent on the latter.

>

> A little bit of history for those who have wondered about these colorful 

> labels.

>

> Gordon Hamilton

>

>

> ----- Original Message ----- 

> From: <nw-mailing-list at nwhs.org>

> To: <nw-mailing-list at nwhs.org>

> Sent: Wednesday, November 01, 2006 9:48 PM

> Subject: Re: Railroad Museum of Virginia

>

>

>> Picture attached: Norfolk & Western C31P caboose 518666 in

>> downtown Portsmouth, VA.

>>

>> Jerry Kay, Portsmouth

>>

>>

>

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