signal questions 3

[NW Mailing List]

Jim,
I'm pretty sure that Ingleside is an intermediate in both directions. 
Intermediates, when there is no train lined in either direction will 
display the best aspect they can for both directions. In this case 
eastbound is clear as there are no trains east of the signal, and the 
next signal is likely an intermediate. As for the westbound aspects it 
would seem to be the next signal to the west is a Control Point, 
therefore the best aspect that can be displayed for this signal when 
nothing is lined is Approach, the Stop indication on Main 1 would give 
me the impression that there is indeed an eastward move lined on main 1.

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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