N&W Train Order Signals

nw-mailing-list at nwhs.org nw-mailing-list at nwhs.org
Wed Sep 13 22:04:31 EDT 2006

On September 5, Eric wrote:


>> In the current issue, August 2006, of 'Mainline Modeler' there

> > are several prototype photos of N&W stations with train order

> > semaphores. Some of the photos show a second arm. In some

> > cases, this is shown dropped to completely vertical.

> >

> > Can anyone describe the rules, or better, scan the portion of

> > the rule book that refers to these. I am aware of the usual

> > rules refering to 19 and 31 orders, but how was this used on a

> > semaphore with positions up 45 degrees, horizontal, and down 45

> > degrees? What did the lower arm apply to?

Since none of the savants and bards undertook to answer Eric, I will.

Answer: Top arm gave block condition; Bottom arm was the train order signal.

Rule 704 from the 1917 Rule Book (found in the section on "Manual Block Rules"):

"The block signal will be used for train orders and all rules applying to train orders will apply to the block signal when used for train orders.

"These signals may be provided with an additional arm below the block arm, which is used to indicate that there are train orders. A horizontal position of this arm, or a red light, indicates - Orders; a vertical or concealed position of this arm, showing no light, indicates - No Orders." (Underscoring added by me, for emphasis.)

This rule did not appear in the 1905 Rule Book. It does appear in the 1917, 1930 and 1945 Rule Books. It is missing from the 1951 Rule Book.

Something I found out in looking up this answer: The concept of "manual block" was referred to in the 1905 Rule Book as "Telegraph Block." By 1917 (and also in later editions,) it had been given the name "Manual Block System."

Eric also inquires about the shape of the ends of the semaphore blades. As a general practice in railroading, the meanings were as follows:

Square end - Home Signal
Scalloped end - Train order signal
Diamond-shaped end - Distant signal
Fish-tail end - Automatic signal

Some railroads color-coded the semaphore blades, too:

Red - Home signal or Train Order signal
Yellow - Automatic signal
Green - Distant signal to a Home Signal

Looking at the N&W Rule Books, it appears that the N&W did not have a hard and fast practice on coloring the blades.

In the earlier years, all semaphores everywhere were "lower quadrant." Sometime around 1911, the industry began switching to "upper quadrant signals," for reasons I will not explain here. It appears that the N&W switched to "U.Q." semaphores for all purposes except Train order signals, which remained "L.Q." The N&W also had a third arm (green in color) on some home signals, and used it as the "calling-on arm."

If you need more, Eric, I'll try to dig it out, or figure it out, for you. But I don't want to tell you how to build a watch, if you've only asked for the time !

-- abram burnett
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