Signal Question and rule term

NW Mailing List nw-mailing-list at
Thu Oct 31 03:11:54 EDT 2013


Thank you for the insight and answering my next few questions with out even
having to ask. I was going to ask if there were any plans to go with a
speed based system when they decided to use Medium in aspects as that's
usually what would follow. However it seems that is not the case.

-Brandon Kaback


Please write that article!

On Tue, Oct 29, 2013 at 10:32 PM, NW Mailing List
<nw-mailing-list at>wrote:

> The matter can be summed up this way: The N&W Operating Rules for 13

> years used the word "Medium" in the names of three of its signal aspects,

> but that word didn't authorize "Medium Speed" (30 MPH) over the turnout.

> The speed over the turnout was "as prescribed" in the Time Table Special

> Instructions.


> The >>ONLY<< N&W Rule Book which uses the term "Medium" in naming signal

> aspects is the 1951 Rule Book. (Those aspects are Approach Medium, Medium

> Clear and Medium Approach.)


> There is one other key ingredient of a Speed Signaling system which is

> missing: the N&W never used "Slow Speed" (15 MPH) signals over switches

> having No. 10 frogs. Slow Speed signal aspects (Approach Slow, Slow Clear,

> Slow Approach) are entirely missing from all N&W Rule Books. Given that

> the N&W had two arms on its home and distant Position Light signals, and

> enough lamp spaces on its Position Light dwarf signals, it would have been

> quite easy (and beneficial) to have given Slow Speed signals where

> required, but they didn't do it. Nor did the N&W ever use Limited Speed

> (40/45 MPH) signals.


> For these reasons, it would probably be best to say that the N&W never had

> a real Speed Signaling system, the use of the word "Medium" for a few years

> notwithstanding.


> As someone on this List remarked a few days ago, the N&W clung to the

> "semaphore mentality."


> In one way, not using the equipment they had to its fullest potential was

> a waste. But in another way, they didn't need a Speed Signaling system.

> Their interlockings were not complex and they did not operate trains on

> close headways. They got by with a simple system that did what they needed.


> Remember the old K.I.S.S. principle? "Keep it simple, Stupid!"


> Nonetheless, I would really love to get inside the head of W.P. Wiltsee,

> the Chief Signal Engineer in the 1930s and 1940s, to find out what he was

> really thinking... especially with some of that stuff he ordered on his new

> CTC equipment in the 1940s !


> -- abram burnett,

> frustrated electron jockey




> ________________________________________

> 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