Branch signaling continued

NW Mailing List nw-mailing-list at
Thu Nov 14 10:18:11 EST 2013

I very will likely have this circumstance on my model railroad and want to reflect it accurately.
Other lines say the South Shore I model don't use the "approach diverging", it will be a simple 1 head signal, but for the N&W you have heavy coal drags and you need time to braking (air response in the train) and adjust to required speeds. Thats what I needed. Why the N&W would apply their signals as they do.

----- Original Message -----
From: NW Mailing List
To: NW Mailing List
Sent: Wednesday, November 13, 2013 4:07 PM
Subject: Re: Branch signaling continued

Yes there is a purpose to have that signal with two heads. Some times the second head may not be used , when? well for instance in figure 5 the home signal is at STOP therefore this signal would display APPROACH for the blue train. NOW move the purple train away from the home signal like in figure 4 then you would get the APPROACH DIVERGING. You would get the Approach in figure 5 due to the fact the signal offers Block Protection and an Approach Signal is more Restrictive then an Approach Diverging. Here is a little more on the difference in the aspects (I pulled the rule book out for this so I could exactly quote the rules):

Proceed preparing to take diverging route beyond next signal at authorized speed.
^With this you are NOT stopping at the home signal, but continuing on via a diverging route

Proceed preparing to stop at next signal. Train or engine exceeding Medium Speed must at once reduce to that speed.
^With this you ARE STOPPING at the next signal. IT DOES NOT matter if you are taking a Diverging route at the next signal or not, because you ARE STOPPING. Therefore you will be well below what the prescribed speed for the diverging route would be. This is because under typical circumstances you with be stopped before getting the signal for the diverging route. If the signal comes in for the diverging route before you get there, you should still be below the prescribed speed as you should be damn near stopped when you get within sight of the signal.

Does this help in understanding the situation at hand?


Nathan Simmons
trainman51 at
On 11/12/2013 09:07, NW Mailing List wrote:

slow down there.

go back that to that figure 5 signal in question. It precedes the turnout and its signal by one block.
Should it be a simple one head signal? Or is there a purpose for having that signal as is?

we're all here to learn


----- Original Message -----
From: NW Mailing List
To: NW Mailing List
Sent: Tuesday, November 12, 2013 2:54 AM
Subject: Re: Branch signaling continued

Let me see if I can drill this concept into your head. Block signals ARE NOT switch indicators! Let me say that one more time...BLOCK SIGNALS ARE NOT SWITCH INDICATORS!!! Therefore, forget the switch points, we are running on SIGNAL INDICATION!!!

Here in Roanoke, you will find that the Forwarding Yard Ladder, The Empty Side Ladder and the Motive Power Ladder all have switch indicators. Their only purpose is to indicate which way a switch is aligned. They offer absolutely ZERO, NIL, ZILCH, NOTHING in the way of block protection! They also DO NOT protect you if the switch points are gapped or lined incorrectly. Why? Because you are working at restricted speed.
Out on the road (and some places through yards), you have block protection signals. These signals control your movement. In order to comply with these signals, one must know the definition of the signal aspects (If I am not very much mistaken, the N&WHS Commissary sells a book showing signal aspects and their definition). I suggest you learn the definitions.
You mention a second head.
For example, what is the difference between an "Approach" and an "Advance Approach" aspect?
The "Approach", by definition, requires you to "Be prepared to stop at the next signal. If exceeding medium speed, immediately take action to reduce to that speed". That means you need to slow down. Even though the next signal may not be a "Stop", you still need to be prepared to stop. You can go a long way and take up a lot of time running on "Approach" signals. OR...
The "Advance Approach", by definition, allows you to, "Proceed prepared to stop at the second signal". It does not require you to reduce speed (Although, in most cases there is a short distance block involved and the need to reduce speed may be warranted.)
Do you understand the difference?
Using this example, on your own, apply this to the difference between the "Approach" and "Approach Diverging" signal aspects. Now tell me why the second head is useful?

Jimmy Lisle

NW-Mailing-List at
To change your subscription go to
Browse the NW-Mailing-List archives at

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the NW-Mailing-List mailing list