Model Board Symbology Questions

[NW Mailing List]

I can answer the R / L question. Nothing to do with the side of the track the signal is on. 6 is the lever controlling the signal and R indicates the direction to turn the lever to clear that signal. It was normal to have two signals which could not be cleared at the same time (typically opposing moves on the same track) to be controlled by a single lever. Turn the lever to the right to clear the R signal and to the left to clear the L signal. Note that on the model board that all R signals govern moves going right on the model board and all L signals control moves going left. It appears that one level for both directions was not done at this tower although I cannot see why. For instance, EB on the EB main is lever 8R while WB on the same track is 18L - both could have been handled by a single lever since you can’t clear both signals at once.

It was even common to have multiple signals controlled by the same lever where the position of a switch determined which of multiple signals would clear. For instance, a simple end of double track could be controlled by a single signal lever and a single switch lever. If you had two tracks going eastbound (which we’ll say was to the right on the model board) merging into one, all you needed was lever 1 to control the switch and lever 2 to control the signals. Both eastbound signals would be designated 2R and when you selected 2R, which of the two cleared depended on the which way the track switch was set. Westbound, 2L cleared that signal but what it displayed (Clear vs. Diverging Clear) depended on the switch (keep in mind that all the operator controlled for a signal was to have it display Stop or have it display the aspect appropriate to track conditions - when an operator cleared a signal, it then operated like an automatic signal to determine what specific aspect to display).

The triangles 9 and 17 were probably derails controlled by the tower. Typically odd numbered levers were used for track devices (switches, derails, and movable point frogs on diamonds) with even numbered levers used for signals,

The four digits signals are automatic that are on the model board for information only. Any signal with an R or L was controlled by the tower. 6R is a bit of an odd duck as it appears to be a controlled signal that governs moves over hand-operated switches (no lever number shown for the crossover or switch on to the Old Main). In addition, there appears to be no controlled signals over those switches westbound. So 6R is what I would call a “hold out” signal. The operator would use it to hold an eastbound train west of 6R when he was unable to clear 8R (the next signal) for a move across the diamond. By doing this, he could protect westbound moves off the Old Main going across to the Westbound Main or at least keep the switch and crossover clear until he could get the eastbound through (also possible is that there were road crossings between 6R and 8R and by holding a train at 6R, you kept them clear as well).

Red and yellow blocks is just to make each block distinctive on the board. No meaning beyond that.

-- 
Larry Stone
lstone19 at stonejongleux.com





> On Dec 28, 2019, at 4:31 PM, NW Mailing List via NW-Mailing-List <nw-mailing-list at nwhs.org> wrote:
> 
> Hi All.
> 
> I have a photo of Circleville Tower’s model board and have some questions about the symbology/nomenclature used. See the attached photo for references.
> 
> 	• Signal 6794 - The symbol for this signal has what appears to be a lower arm. Signal 6778 does not have this. What is it?
> 	• Signal 6R is similar in appearance to 6778, except that 6R has a “hollow” quadrant. What does this difference indicate? Is it a home signal compared to an ABS signal perhaps (6R seems to be within the scope of the tower, based on dad’s recollections).
> 	• Signal 6794/6778 are numbered based on milepost; what does 6R, 10L and similar mean? That they are within the interlocking plant?
> 	• What do Triangles 9 and 17 on the Old Main indicate (for reference, the old SV main was used to switch local industries, and is still in place today)
> 	• Similarly, does the R / L simply indicate which side of the track the signal is on? If so, why is this needed vs. just having unique numbers?
> 	• Is there any significance to the red/yellow alternating block colors beyond making it easier to see where each starts and stops?
> 
> <IMG_1218.jpeg>
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