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Semaphore Traffic Signals.

Started by thenetwork, August 02, 2024, 05:38:50 PM

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thenetwork

One of the more noted traffic signals that is not in existence anymore are rhe intersections that used STOP and GO semaphores in addition to the 2-segment red/green lights.

I never saw one in use in person, but it seemed a lot of cartoons into the 1970s would use this type of traffic signal as well as many older movies and TV Shows.

Despite that being said, it seems like the semaphore signals on roadways were only used in the Southern California/Los Angeles area

Were there other cities or regions that used these types of signals?  It seemed that most other municipalities used simpler 4-way, 2-segment signals at their intersections. 


Dirt Roads

In New York, semaphore traffic signals were common in New Rochelle, North Pelham and Pelham Manor by the late-1920s.  These were in particular use along the Boston Post Road (now US-1), but there were a number of other intersections so equipped. 

There was a famous issue in Pelham Manor whereby the new semaphore stop light caused trucks to stop frequently in the middle of the night, and the noise of the trucks pulling out when the light switched from "stop" to "go" would disturb the local residents.  In many cases, the semaphore traffic signals were replaced with simple "caution" flashers to allow trucks to avoid coming to a complete stop.  However, the need for improved safety eventually resulted in more semaphore traffic signals to be installed throughout the Pelham area.

Dirt Roads

There were several brands of semaphore traffic signals back in the 1920s, including the ACME signal that was manufactured and popularized in Los Angeles.  But I have been unable to track down any of the other semaphore signal manufacturers.  One issue is that the term "semaphore" was in common use back in the 1910s and early 1920 for non-signal traffic devices that were manually controlled by city police officers, so that term was not used with respect to mechanized traffic signals (including those with semaphore arms displaying "stop" and "go" signs) in order to avoid confusion.

I'm particularly interested in the circular mechanized semaphore display sign (commonly referred as a "banjo semaphore"), that was also fairly common in Los Angeles in the 1920s.  I still can't determine who was the manufacturer.  Technically, it wouldn't be considered as a "traffic signal" in today's vernacular, since it did not have red light/green light displays (what we railroaders call "aspects").

Most resources indicated that both the ACME semaphore traffic signal and the so-called "banjo semaphore" were in widespread use in cities other than Los Angeles.  Not sure about the others.  Stay tuned.

Dirt Roads

I didn't find any of the other brands of automatic semaphore traffic signals, but I did find the manufacturer for the famous/infamous "banjo semaphore".  It was manufactured by Universal-Waterhouse Signal Corporation of St. Louis.  There was an advertisement on the inside back cover of the April 1928 edition of Nation's Traffic Magazine showing an installation in Pasadena.  (There's a different ad on the inside front cover of the May 1928 edition as well).

Amazingly, the "banjo semaphore" shown here is indeed a true "traffic signal", as it is equipped with red and green lenses (plus what appears to be an amber lens at the bottom of the cluster, probably used for flash mode at night. 

Here's a link to the Google Books edition:  Nation's Traffic Magazine (Feb 1928 thru Feb 1929).  Scroll up just a tad to see the installation in Pasadena.

Back to the original OP topic:
Another ad in the July 1928 edition shows a small insert with the typical "banjo semaphore" with no lights, and also indicates that the Universal-Waterhouse Signal was being used in London.  You can find it easier by starting at the last page of the aforementioned Google Books version, and scrolling up to the a reprint in the inside back cover of the February 1929 edition. 

For the record, ACME Traffic Signal Company grabbed the inside front cover of the September 1928 (not avery good copy, but might be of interest to some).  Fans of "old signals" ought to have a field day flipping through all of these old advertisements.

steviep24

#4
Acme traffic signal (probably from LA)
https://www.youtube.com/watch?v=ooF9il6DZ-w

San Francisco had this thing.
https://www.youtube.com/watch?v=exC7LI6slgQ

Dirt Roads

Quote from: steviep24 on August 10, 2024, 03:35:26 PMSan Francisco had this thing.
https://www.youtube.com/watch?v=exC7LI6slgQ

More on this.  It was known as the "Wiley birdcage signal".  Looks like they were used in Los Angeles also.  I'm wondering if its inventor, R. W. Wiley, was the same fellow who is listed as a signalman on the Santa Fe railroad in Los Angeles back about the same time.

Henry

BTW, when did the three-light setup that added a yellow signal for "caution" become mandatory? I've learned that Canada still uses semaphores, but with red and yellow signals for construction zones.
Go Cubs Go! Go Cubs Go! Hey Chicago, what do you say? The Cubs are gonna win today!

Dirt Roads

Quote from: Henry on August 13, 2024, 10:23:54 PMBTW, when did the three-light setup that added a yellow signal for "caution" become mandatory? I've learned that Canada still uses semaphores, but with red and yellow signals for construction zones.

In a way, I've been chasing this same question ever since thenetwork opened this thread.  As a railway signal engineer, we have a lot in common with traffic signal engineers and traffic control engineers (which are two different specialties, albeit some smaller agencies have one engineer that can work both sides).  The three colors were standardized by railroads long before employed as traffic signals.  Of course, railroads use green-yellow-red (top to bottom), whereas "stop lights" use red-yellow-green.  And that fact comes directly from how railroad semaphore signals are designed (more below).

The "Original MUTCD" developed by AASHO (the 1927 edition of the Manual and Specifications for the Manufacturer, Display and Erection of U.S. Standard Road Markers and Signs) did not address traffic signals.  Therefore, many folks trace the standardization of traffic to the creation of the Institute for Traffic Engineers in October 1930.  However, I believe that credit should go to the Eno Foundation for Highway Traffic Control created by William Phelps Eno in 1921. 

In his 1926 book Fundamentals of Highway Traffic Regulations, Eno discusses his efforts to get cities to adopt "Suggested Standardized Enabling Ordinances" with the goal of a "standardized State of Federal law" regarding traffic control, including signals.  In February 1920, Charles Thaddeus Terry Esq., professor of Law at Columbia University and member of National Conference of Commissioners on Uniform State Laws (now Uniform Law Commission), wrote back to Eno with a proposed national legislation that included language such as "mayors shall adopt and enforce the General Traffic Regulations", a nod to the term that Eno himself had coined and was already adopted by many cities across the United States (often "General Highway Traffic Regulations").  Anywhoosit, in this book Eno writes that "The experience of the railroads has demonstrated that the following colors should be employed: Red for Danger // Yellow for Caution- Proceed slowly and with care // Green for Safety-Proceed as usual.  The three colors named should therefore be used consistently for these traffic signs and lights". (the word "lights" meaning traffic signals and illuminated semaphore signage).  By Eno repeating the safety language used in railroading,  this certainly locked down the concept of three-light traffic signals.

So back to the primary difference between railroad signals and traffic signals.  Unlike stop lights, railroad signals have traditionally been designed as fail-safe, both electrically and mechanically.  With railroad semaphore signals (and similarly designed railroad "searchlight signals" that do not employ semaphore arms, the mechanical fail-safe design requires that the arm drop to the stop position (using gravity) when electricity is removed from the signal for any reason.  The most common design used the light fixture as a counterweight, and when doing so, the lenses appear to be arranged as "green-yellow-red" when the semaphore is displaying an "approach indication", that is yellow aspect (amber lens illuminated). 

Many railroads preferred to use amber lenses in both positions other than "stop indication", which was red.  Accordingly, when Position Light Signals were developed by the Pennsylvania Railroad (PRR) in 1915, they set amber lenses in most positions, with the "proceed indication" as yellow-over-yellow and the "stop indication" as red-beside-red with two yellows set at the 45-degree mark in the "approach indication", all to mimic the semaphore arms.  Color-position light signals developed by the Baltimore and Ohio Railroad (B&O) in 1918 replaced the "yellow-over-yellow" with "green-over-green", memorializing the concept of "green on top".  All other railroads quickly adopted the "green on top" form of signalling.

Dirt Roads

I should add that the "red-on-top" philosophy of traffic signals was subject to significant debate.  Going back to the beginning, there were also arguments about whether the "stop signal" used by traffic cops should be arm pointed out or arm straight up (and waving until cars stopped).  But in between, I don't recall any arguments about the position of the semaphore arms, as it seems that signal mechanism engineers quickly agreed that the arm down position was both efficient at stopping trains (and automobiles), as well as simple to achieve for safety purposes (with gravity drop upon loss of electrical signal, even when not designed as a fail-safe device).

Then comes the infamous Darley Signal, which remained popular well into the 1950s.  Designed with only three bulbs for a four-way signal, the W. S. Darley and Company dominated the traffic signal market because of its low purchase and maintenance costs.  Of course, this means that one direction gets "red-on-top" and the gets "green-on-top".  I'm fascinated with the use of aluminum paint on an aluminum frame, in order to eliminate the need for repainting when the paint chips off.

lepidopteran

#9
For the record, there are a few semaphore traffic signals at Disney's Hollywood Studio theme park in Florida.  I'm guessing that these are repros rather than original Acme signals. But I wonder how accurate the details are to the real thing?
https://wdwnt.com/2024/06/final-traffic-signal-repaired-hollywood-studios/

Regarding yellow lights, I'm not sure when they first became mandated, but I do know that New York City was late in adopting them.  I think the 3-section R-Y-Gs only started to appear in the 1950s. There were a lot of 2-section setups in use in Brooklyn back in the '70s. It wasn't until circa 2000 that the last of these, located in the Rockaway Beach section of Queens, finally vanished for good. Some had even been retrofitted with LEDs by then!

This vintage Sesame Street film about traffic signals shows a few 2-section units in operation, including a classic 4-way with cutaway visors; I think it was made by Ruleta.  Though the film doesn't show it, the old 2-sections would simulate a yellow clearance interval by having the red and green aspects lit simultaneously.

Dirt Roads

Quote from: lepidopteran on August 15, 2024, 10:53:01 PMFor the record, there are a few semaphore traffic signals at Disney's Hollywood Studio theme park in Florida.  I'm guessing that these are repros rather than original Acme signals. But I wonder how accurate the details are to the real thing?
https://wdwnt.com/2024/06/final-traffic-signal-repaired-hollywood-studios/

They are real.  My understanding is that out of the 11 remaining ACME Semaphore traffic signals remaining, five of them are located at Disney's Hollywood Studios. 



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