Nostalgia & History > Semaphore Signal Sunday

More from the Lee Meyers slides

#1.....Stronghold, CA. where the BN crossed the SP Modoc. Back on 5/24/ 1987 there was a Semaphore and switch lights...Today its a tri light and switch target.
#2.....SP Syskiyou Line at Hilt on 5/25/1987
#3.....SP Syskiyou Line North of Medford one mile from Central Point, Oregon on 5/26/1987

Hope you enjoyed these and they are all gone

Thanks for looking and See You Down The Tracks

Jay

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#2 is gorgeous for multiple reasons! I'll bet your Mr. Meyers was really wishing for a train with that dynamic sky...

Lance

I don't know a whole lot about semaphores but I sure do love them! I miss them! Thanks for posting!

Any explantions on the blade colors?

SD45X Wrote:
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> Any explantions on the blade colors?

On the SP the following applied.

Square Blade:

1. Red with white strip -- Home block, white stripe indicates it is an automatic signal.
2. White with black strip -- Reverse side home block, shows train crew that opposing signal blade is a home block automatic signal.


Fish Tail Blade:

1. Yellow with black strip -- Distant block, automatic signal (reduntant as all distant signals are automatic signals).
2. White with black strip -- Reverse side distant block, shows train crew that opposing signal blade is a distant automatic block signal.

If the home signal blade (square blade) was solid red (no white strip), that would indicate it is a home block controlled signal (found at interlockings and CTC). The back would be solid white as well. As stated above, all distant blades had stripes.

In the first photo, the switch is for a siding that
goes to a grain elevator in back of the photographer.

Here is a 2012 Google street view from about the same
location.
https://www.google.com/maps/@41.9094596,-121.4172935,3a,55.1y,327.78h,80.35t/data=!3m4!1e1!3m2!1sNFkKH4pSVMjjcYSrigOpBg!2e0

BCHellman Wrote:

> 1. Red with white strip -- Home block, white
> stripe indicates it is an automatic signal.

Thanks for the explanation. Could you also tell us what a "home block" is? I'm familiar with home signals in controlled situations at interlockings (like the BN signals pictured at Stronghold), but what did "home" mean in the case of a signal like ex-SP signal 4442 above, which appears to be an automatic signal on single track with no switches in sight?

While we're at it, does anyone have pictures of the distant signals approaching Stronghold on the BN?

Evan_Werkema Wrote:
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> BCHellman Wrote:
>
> > 1. Red with white strip -- Home block, white
> > stripe indicates it is an automatic signal.
>
> Thanks for the explanation. Could you also tell
> us what a "home block" is? I'm familiar with home
> signals in controlled situations at interlockings
> (like the BN signals pictured at Stronghold), but
> what did "home" mean in the case of a signal like
> ex-SP signal 4442 above, which appears to be an
> automatic signal on single track with no switches
> in sight?

Perhaps a better term than block would be blade, as in home blade and distant blade, but the meaning is essentially similar in that the home relay (abbreviated in prints as HR) related to the home block controls the home blade (signal) and the distant relay (abbreviated DR) related to the distant block controls the distant blade. It should be noted that the distant relay (blade) is always wired through the home relay (home blade), such that if the home relay (home block) is dropped (occupied), the the distant blade will be at it most restrictive.

The home block is the block in front of the signal. Sometimes it can be more than one block in front, depending upon the protection and type of signaling circuits. So the home block(s) control the home relay, which in turn control the home signal (abbreviated HG), and in this case the home blade. In fact since SP in ABS was mostly overlap, under most circumstances the home blades in SP ABS the control protection for the home block (HR) extended beyond more than one block, making the home block multiple blocks. The only exception that I've witness and seen on prints is the approach signal to a siding, where the home block is one block to the head block of the siding.

You've probably seen pictures on SP double track where only one home blade is the signal. The Cal-P and the double track from Tehachapi to Mojave come to mind. In these cases the home block was at least two blocks (they were gone before I ever saw either example, so I never got to see exactly when they cleared nor ever saw a print). This would make sense since you can expect a train that doesn't have an appoarch signal to stop in back of the signal.

In the same vein the distant blade (signal) controlled by the distant relay (abbrevieated DR) (block) may be controlled from several blocks. Again, it depends on the territory and circumstances.

A common pattern on single track SP in the Style-B era from the 40s to 2000 was to favor a combination of 2 and 3 indications (single arm vs. double arm), with the double arm at the approach to a siding and at the entrance to a siding and single arm at all other locations in relationship to the siding (intermediates, exit of a siding, etc). However, where there was a high amount of switching activity or traffic, the SP would use "double-doubles." The territory around Medford, as seen in signal 4442, was such a place. The Phoenix area had double-doubles. Around 1950 the SP replaced single-arm with double-doubles and re-spaced them on the Bowie Subdivision (Stormy) from Mescal to Lordsburg (only to pull them less than 8 years later in the CTC project). Sometimes the rewiring meant that they replaced the semaphores with searchlights, as was done on the Guadalupe Subdivision in the mid-50s. The South Line between Douglas and Bisbee had double-double upper-quadrant signals (probably because the number of ore drags between the mines at Bisbee and the smelter at Douglas), but they had single arms interspersed as well.

In APB the home block or control depends on the movement of the stick relay, so the home block, control or signal can be either the block in front if the movement is in the direction of the signal, or until the siding; however many blocks that might be.

I hope the explanation doesn't confuse the matter.