signal questions 3

NW Mailing List nw-mailing-list at nwhs.org
Wed Jun 3 14:45:33 EDT 2015


I forgot to mention Jim, Willowtown is an intermediate in the middle of 
2 control points, and if you look closer the lights around the curve are 
of an approaching train that is on the near track.

Nathan

On 6/3/2015 03:49, NW Mailing List wrote:
>
> At first glance, 
> http://www.railpictures.net/viewphoto.php?id=472679&nseq=319 looks 
> like a recipe for disaster atIngleside. But what is really going on 
> here? I believe the camera is looking into the aspects that an 
> Eastbound movement would observe and it shows clear for both mains. 
> Because of the long exposure, we can also see reflections of the 
> Westbound aspects, and they are stop and ?approach? Why would you ever 
> want opposing movements to both see “go ahead” aspects for the same 
> track at the same point? Let's dig a little deeper. The Eastbound 
> signals are a control point (note the single lights under the top arm) 
> for the next block. However, the Westbound signals are intermediates 
> (automatic). It appears that the dispatcher has set routes Eastward on 
> both mains, thus the clear aspects. One of the Westbound intermediates 
> is showing stop and proceed, as I would have expected, but why does 
> the other show approach? Under the “tumble down” operational scenario, 
> I was under the impression that when a route was established between 
> control points for a movement in one direction, all the intermediates 
> between the two control points were immediately dropped to their most 
> resticting aspect, i.e. stop and proceed. My question is: why does the 
> one intermediate show approach, and why is this safe? Another example 
> of this seemingly unsafe behaviour is shown in 
> http://www.railpictures.net/viewphoto.php?id=510649&nseq=1 at Willowton.
>
> Thanks, Jim Cochran
>
>
>
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-- 
Nathan Simmons
trainman51 at gmail.com
http://www.t-51.org
KI4MSK

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