How Vintage Railroad Signals Work: The Inside Story

[@quintinivey9359]

20th-century tech at its finest. Whoever got these signals, thumbs up on saving them.

[@paullubliner6221]

The Style "B" was introduced in the 19th Century.

[@Qrail]

It’s nice to see the old timers that help keep the signal garden active. And good job explaining what the signals do. Thanks

[@derrickodyes1934]

That signal equipment is built to last forever and very cool. Thanks for showing Mark

[@glennfoster2423]

A special thanks to the work the Museum Signal Maintainers do. How convenient they don't have to drive for miles (with one exception) to fix stuff.

[@awalker1829]

One item that isn’t frequently discussed is the history of signal colors. Originally, the colors were red for danger, green for caution and white for clear. Yellow was not used for caution until Corning glass perfected a yellow glass that did not have a reddish or greenish hue.

[@MarkClayMcGowan]

Good info. Thanks!

[@paullubliner6221]

@@MarkClayMcGowan Not quite. -----Dr. Churchill's 1905 "yellow" glass permitted a portion of both red and green light to pass through it. ---The Baird Nels yellow roundel was introduced in 1898 and the New York, New Haven and Hartford R.R. was the first to use them in Boston's South Station, where the "Railroad Signal Club" made an in person trip. The Railroad Signal Club was the predecessor of the R.S.A., the A.R.A. Signal Section (est. 1919) and the A.A.R.'s signal section (est. 1937) The Erie adopted red, yellow and green in 1906 while most other roads came along in the teens. The one main hold out on red, green and white was the C&O, resisting until as late as 1922. They even fitted red, green and white (clear) inner doublet lenses into their US&S Style R color light signals until that late date. Physicist Dr. William Churchill left Yale U. for Corning Glass Works in 1903 and his response to the yellow roundel and an imminent industry wide shift to red, yellow, green to replace red, green "white", was his invention, the Lunar White roundel. L.W. gave the same night-time viewing range as red and green and was not easily confused for clear as was yellow at a distance, or when there was heavy smoke; red, as were both true with the yellow glass. ---Read his paper the "Roundel Problem" presented to the R.S.A. on October 11, 1905, only a day after that well known patent filing. In that presentation he made it quite clear that he was very disappointed the L.W. roundel wasn't adopted as standard and simply installed in the spectacle castings already having space for a color for clear instead of a bare kero flame. ....And lastly, along with Dr. Gage, they patented the "Doublet Lens" design for color light signals in 1911.

[@tomshank4446]

It's my understanding (or misunderstanding) that almost all of these older signal types were designed so that if power was lost to the signal, the weight of the mechanism would cause the signal to go to red automatically as a safety design.

[@MarkClayMcGowan]

That is true. The mechanisms inside searchlights were also failsafe, with a counterweight that rocked the head to red if there were a problem. Thanks for checking it out!

[@roberttrometter5788]

Mark, you did a great job at explaining the signals. I want to thank the guys who take care of the signal. They are true railroad signal operators and maintenance guys who know their stuff. Thank your and Thank you Mark for this great piece of video. Robert

[@ocsrc]

110 volt DC is a lot of power. Why so high ? That would be very dangerous to touch. 12 volt seems to be the voltage now

[@MarkClayMcGowan]

@@ocsrc If you're talking about the dwarf semaphore, I don't know why they went with that. Perhaps, since it was in a location where AC was readily and consistently available, it was just easier and less expensive, but that is pure speculation!

[@charlesglandon7840]

Thanks for doing this video great information on the inner workings most of us never even thought of. Thanks to all the "Old Timers" (I'm one too I'm "74) for their hard work their knowledge needs to be shared so this history will not be lost. Thank you Mark for all your videos.

[@glengriswold9986]

Mark, what a great job covering the mechanics of these signals. Just a side note, Frank Griswold purchased the Magnetic Signal Co. in the early 1900s. So all the wig-wag type signals were from one supplier.

[@paullubliner6221]

Not true, look up US&S DW "Automatic Flagman".

[@glengriswold9986]

Thanks for this reference Paul. There were several spin-off designs of Frank's products. I didn't take those into account.@@paullubliner6221

[@johnwinden8511]

Hi Mark, thank you so much for the video, I really did enjoy it. The inner workings of those devices were simple and strong and would last a long time. The nice part is that they mostly made sense as to their workings, no magic from a computer, easy to diagnose. As an old retired mechanic I can appreciate the simplicity, like cars once were. There was an old station near my house when I was a kid and they had the semaphore out front. I’m going to assume that was there to get a train to stop? We also had some wig wags around here, Tacoma wash., the last of which, believe it or not, was removed just a few years ago when they upgrades a secondary line to run passenger transit trains. Thanks again, much enjoyed.

[@MarkClayMcGowan]

The semaphore at the station was likely a train order board, which told a crew whether or not they had to pick up orders meant they did not, horizontal meant they did. The orders were handed to the crew on the fly. Here is the link to a video I made at the Santa Susana Depot Museum in which that process is gone over in detail. kzbin.info/www/bejne/eXvJcodretuKd9k

[@chuckmorris7043]

I also worked for the telephone company, and seeing that 'Gold Plated wiring work, I am really impressed..,, That is beautiful craftsmanship.

[@rogerpenske2411]

Except for myself and a small handful of other people, the details on the electrical probably went over most peoples heads, but you kept it brief and interesting with flashing the lights. Who doesn’t like flashing lights?!

[@Benjamin-David]

Amazing. I’ve been to the park many times and never have I ever had the pleasure of seeing the single operating let alone the internals.

[@MarkClayMcGowan]

The museum is going to start demonstrating them one Saturday a month, and possibly on First Friday evening downtown. Once they get the schedule firmed up, I'll make a short video here, and post it on my Facebook Page (Mark Mcgowan) as well. If you're going to be in the area and want to see them at another time, let me know in advance and I'll try to get up there, whether or not the museum is open, and show them off!

[@StormySkyRailProductions]

Fantastic video Mark and we sure enjoyed watching. Have a wonderful rest of your Wednesday.(Steve)

[@kens.3729]

Signals were Very Interesting on how these were Designed years ago. Impressive to Keep Thousands of Railroad Employees and the General Public, Safe. 👍🙏

[@johncamp2567]

That was a remarkable demonstration!! Where would one ever get to see those antique mechanisms? Excellent!!

[@paullubliner6221]

A lot of museums have such displays also (Orange Empire in Perris, Ca., or the Los Angeles Live Steamers for two such museums) and too, fair number of guys have private collections as this.

[@MarkClayMcGowan]

I've been to many museums and have never seen such an extensive working collection as this. This one started out as the private collection of the late Bill Stokoe (1922-1999), SP Tehachapi Signal Supervisor 1967-1989.

[@FernandoRojas-do9qj]

First I want to greet you with a big hug from a railway colleague... I treasure your videos, through them I witnessed your recovery from covid 19 and how to overcome it, only a tough guy with a back of steel can overcome it... I send you a big hug and I want you to know that on the other side of the world (Argentina) there are people who follow...

[@MarkClayMcGowan]

Thank you! I appreciate the support and always love hearing from subscribers in other parts of the world!

[@bonesthims-li5se]

Some oldies but goodies .....that was good.........Bones

[@johnschultz9023]

Upper quadrant means it moves from horizontal to vertical in an upward direction vs moving downward to clear.

[@jessestarks3128]

That was interesting considering the scarcity of many of these signal types in the field. Keep up the great work!

[@paullubliner6221]

Scarcity? THERE AREN'T any but a dwindling handful of T-2's in N.M.

[@MarkClayMcGowan]

@@paullubliner6221 that is the definition of "scarcity".

[@markdavid7013]

Cool! I always wanted to know how a Wig Wag crossing signal worked.

[@captainkeyboard1007]

Gentlemen, I thank you for showing the real works of the signal apparatus, and all other railroad equipment that we would not ordinarily we [railfans] and railroad buffs would get to see. The parts of the signal lights are mostly mechanical, that could be easy to maintain more than the electronic parts. Mark Clay McGowan, I wish you "Happy Railroading!" even if you are retired.

[@doncheeto8549]

Videos like this is why i subscribed to this channel sir, great job 👏

[@OnefastAZfarmtruck]

It’s nice to see some of that stuff preserved. I almost shed a tear watching UP rip out the us&s search lights along the salt on sea with a torch and a grapple thumb. Watching them get thrown violently in a scrap dumpster in Mecca Ca hurt

[@MarkClayMcGowan]

We scrapped piles and piles of the Fresno sub during that project. I managed to salvage a couple for friends though

[@randydobson1863]

hello mark it's is randy and i like yours video is cool thanks and i like vintage railroad signals work thanks and super cool railroad signals thanks mark and good friends randy

[@jovetj]

Great video!! Love to see these neat old _iconic_ signals preserved as they should be!

[@AMTK90200]

Nice video, I like the semaphore signals.

[@strobelightbrian]

Thanks for sharing and showing us this!

[@remylopez4821]

Thank you very much Mark that was a fascinating video and to the gentleman that restored and maintain that equipment thumbs up I was also digging that old Willys Jeep at about 13:23

[@ccrx6700]

Excellent presentation Mark ❤👍😎

[@majikglustik9704]

Hey Mark! Sooo cool; a niche for you. Hope to see you and Will soon.

[@RFMCabooseNP1713]

Fantastic.

[@stevemellin5806]

Thank you

[@johnnyeveritt5695]

Hay Mark : Given the dated electro-mechanical components [ The inner-workings of Pinball machines immediately come to mind ! ]; the durability of repeated; reliable performance under ALL weather conditions over the years remain as a compliment to the design engineers of these important RR safety machines ! ✊️👊🤙😁

[@matbr6949]

I thought of pinball, too!

[@johnnyeveritt5695]

@@matbr6949 Ja : The sheer NUMBER of Relays and related wiring-looms that controlled Pinball machines was unreal; especially given the abuse of forceful Body-English inevitably resulting in * TILT * ! ! 👏😄

[@angelica351a]

Very cool-thanks

[@billking8926]

Great demonstration Mark. Please remember that the correct name is "Grand Central Terminal" not station. Thanks for all your informative posts on the inner workings and uses of signaling.

[@joefin5900]

Grand Central Station is the Post Office facility adjacent to the terminal.

[@billking8926]

@@joefin5900 Thanks for the info Joe. Never knew that!

[@glennfoster2423]

These are examples of electrical/mechanical logic driving electrically functioning motors, relays lights, signs and bells. These beefy concoctions of parts that go white and clunk revolutionized railroad (and all) transportation across the world. The safety and efficiency gained is remarkable. The museum is a wonderful presentation of that historical leap. A note about semaphore arms. "Quadrant" refers to the part of the circle the semaphore arm uses to display the messages of aspect and indication, with zero at the top of the circle. Upper Quadrant" refers to the 90 degree part of a circle in the clockwise direction between zero and 90 degrees, and lower quadrant refers to the 90 degree part between 90 degrees and 180 degrees. The style B semaphores use less than the 90 degree position at 180 degrees. Golly, the weeds are so cool!

[@paullubliner6221]

Glenn, there were quite a few 0-90 degree three position lower quadrant semaphores. The last being in service in St Louis.

[@glennfoster2423]

@@paullubliner6221 You are correct. I should have been more specific about the Style B units.

[@paullubliner6221]

@@glennfoster2423 The CRI&P had 3 position, 90 degree L.Q. Style "B's" Glenn. "B Units" to me means something entirely different....

[@lynnmccurdythehdmmrc2561]

Thank You Mark, great Video.

[@MarkClayMcGowan]

Thanks, Lynn!

[@NE-Explorer]

Great job Mark!

[@TNRailProductions_01]

Great video.

[@ttgandydancer]

Great video Mark, it's a shame I missed this by a couple days.

[@MarkClayMcGowan]

Once all the proper board members give the go ahead, I will be doing demonstrations on the signals operating once a month. If you're going to be in the area and want to get a peek inside these things, let me know at least a week in advance and I'll try and work it out!

[@milwaukeeroadjim9253]

Illinois Railroad Museum has a large collection of signals too. Did the railroads have DC current running along the tracks for signals or did they have to have transformer boxes nearby. Nowadays I see transformer boxes powered by the electric company providing for signals and gates.

[@MarkClayMcGowan]

We had AC on the poleline that was rectified rectified inside the cases and cabins to operate local equipment like track drivers, switches and signal lights. DC circuits were also on the line to send information from signal to signal. Here is the link to a video I made about the poleline, which no longer exists. Today, most locations have their own power. Sometimes, underground cable is used to get power to remote locations, and all signal circuits now use the rail for both track and information control. kzbin.info/www/bejne/mWHXe2mBqNtlfrs

[@paullubliner6221]

10 volts DC was the original standard current for block detection. Floating AC came later.

[@MarkClayMcGowan]

That's true for block indications on the line, but track circuits have always been less than 2 vdc, provided by batteries until the 1980s, when we began installing 1, 2, and 3 TC units (in my corner of the world!). I'm not sure what you mean by floating AC, but we do use AC overlays for certain approach circuits, but not for track circuits.

[@paullubliner6221]

@@MarkClayMcGowan Google the Signal Engineer for floating A.C.

[@edwinsinclair9853]

The lower quadrant semaphores (style B) were used in the Western U.S. by both the Southern Pacific and Union Pacific and date from the Harriman Era of both railroads. The upper quadrant US&S semaphores were used by the Santa Fe, Northern Pacific, and Great Northern. Interesting to note that you used to be able to tell whose railroad tracks you were looking at by the signals and the lineside poles.

[@paullubliner6221]

ED..... Santa Fe used Style "B's" as well. They were the first electrically approach lit signals in the U.S., or anywhere.. As for N.P. and G.N they also used lower quadrant semaphore signals. It depends upon "when". If you doubt me I suggest that you start collecting older editions of railroad "Rules of the Operating Department" books. In 1981, on a road trip with friends on the way to Portland to see the newly painted painted S.P. GS4 into Daylight colors, I pointed out were were following the "Wrong Railroad" as the searchlights were G.R.S. Type SA's, and not the S.P.'s US&S Style H or H-2 searchlights. I was correct and it really irked one of the guys that I was right as he was driving, .....and an AT&SF employee!

[@jovetj]

11:48 That's not what "upper quadrant" means. It means the blade moves in the upper quadrant (think Cartesian coordinate system), or upwards from Stop (horizontal), whereas lower quadrant move downwards from Stop (horizontal). But, it is true that the lone 3-position upper quadrant semaphore can convey exactly the same information as the two-arm lower-quadrant semaphore just shown can. 👍

[@jonwebster2611]

AGREED!! Thank you for pointing out the only error I heard in this excellent video!!

[@MarkClayMcGowan]

That has already been pointed out to me. This is why I did the disclaimer at the beginning of not being conversant with these signals! Thanks for checking it out!

[@jovetj]

@@MarkClayMcGowan It's all good, Mark!

[@jikutokaharu5634]

Thanks for the interesting video! We still have searchlight traffic lights, although this is very rare. The largest number of lens traffic lights, as at 20:26

[@paullubliner6221]

"Traffic lights" are highway signals, not "railroad". Railroad came in , "Block", "Interlocking", "Train Order" or "Centralized Traffic Control" types.

[@jikutokaharu5634]

@@paullubliner6221 Thanks for the clarification! Of course, I meant railway signals. Thanks for the clarification! Of course, I meant railway signals. I work for the railway and maintain the electrical centralization.

[@kens.3729]

Jim Jury must have Worked for Pacific Bell Telephone Company before they were Acquired by Southwestern Bell Corporation (SBC) in the Mid-1990’s (1995). 👍

[@MarkClayMcGowan]

I've never met him and ho no longer lives in the area, so I don't know.

[@johnschultz9023]

The GRS Model 2A uses a buffer resistor that cuts in and in in parallel with the motor armature and field ( series wired provides more torque than shunt wired motors).

[@jonathanhusner8756]

I have a feeling the upper quadrant semaphore was off the Santa Fe in NM they used that style semaphore

[@paullubliner6221]

Or Colorado, or Kansas, or Missouri, or Texas etc.

[@macmedic892]

I’d have loved to see the mechanism that rotates the stop sign, particularly how it turns back after what seems like quite a delay after the lights stop flashing.

[@MarkClayMcGowan]

I go over that operation at 7:20. It's just a counterweignt attached to a gear

[@jovetj]

12:10 Blade interference on semaphores wasn't a problem. The UQ semaphores typically used blades 3 feet long and were spaced 7 or 8 feet apart on the masts. (A three-arm semaphore typically had a shorter blade on the bottom, only used for what would today be called a _Restricting_ indication.) The LQ blades were usually about 4 feet long, and, while spaced closer on a mast, didn't typically go fully vertical (except for very early types, and perhaps 1-arm train-order signals) ,.

[@jovetj]

@@paullubliner6221 Yeah, not exactly. The first six inches of most UQ blades don't do a whole lot. So the usable part is 3 feet.

[@paullubliner6221]

Not exactly. The R.S.A. (Railroad Signal Association) standards set in 1908 are 42" long blades for upper quadrants and 48" long blades for lower quadrant. This was concurrent with the Type "A" U.Q. spectacle so few seem to realize was its origin. Union started with a 6 foot spacing for the home and distant A.B.S. blades on their "B's" (as on my own examples) but around 1911, US&S increased the spacing to 7 feet as the new standard for improved sighting distance. ---On three arm U.Q. semaphores, the R.S.A. standard spacing was top to middle blades 7 feet, with middle to lower blade spacing being 6 feet along with a 2-1/2 foot blade on the bottom arm. This served the same function as a dwarf signal. Erie used a 12 foot spacing between their pointed A.B.S. three position upper blades on their well known Union Style "S's", and the lower blade 30" long and square for "Train Order" (crossover) dispatcher controlled operation.

[@paullubliner6221]

@@jovetj You ARE joking right? In 60 years of actively looking, I have NEVER seen a 3 foot semaphore blade anywherre in the U.S. The R.S.A. Standards were universally followed, EXCEPT on the Lehigh Valley with 48" U.Q. blades on their top-of-mast Model 2A's, while over on the B&M, the CNJ and the Erie; their US&S pneumatic and electric L.Q. semaphores had 42" blades. ----YOU KNOW, there's reality and then there's the unhealthy state of self delusion Jovetj....

[@jovetj]

@@paullubliner6221 Self delusion?

[@SandBoxJohn]

Minor nit pic on the description of the GRS Model 2A Semaphore. The location is actually named Grand Central Terminal.

[@MarkClayMcGowan]

Yeah, I've already been called on that a few times! What do you expect from a West Coaster?!

[@SandBoxJohn]

@@MarkClayMcGowan West Coaster are not the only people that have called it that.

[@paullubliner6221]

@@SandBoxJohn That's because before the opening of GCT in 1913, the original Manhattan terminus was known as Grand Central Station.

[@SandBoxJohn]

@@paullubliner6221 Actually the terminal before the existing terminal was Grand Central Depot.

[@paullubliner6221]

@@SandBoxJohn Show valid period proof of your claim, please. I looked in one of my signal books, Block Signals, by Braman Adams, published in 1901, and it has the 1901 track diagram located at East 42nd Street and 4th avenue NYC (same a the present site) and plainly the track diagram was labeled as and the facility therefore called: "Grand Central Station".

[@ericallen9415]

This is a great video! I wish the bells wouldn't have cut the volume of your voice, but the bells were meant to be heard by motorists with closed windows, not the voice of a videographer! Haha! But a fascinating video! Thanks for posting it. Subscribed!

[@MarkClayMcGowan]

Actually, the bells (gongs) are to warn pedestrians. I missed that question on my second phase signal training test!

[@jeffreykornspan9053]

THanks Mark, It would be safe to say that "they don't make them like that anymore"! Enjoyed your video. jk

[@Franklin-jj4jz]

6:38 Either a UFO or some hurtling piece of machinery from Edwards AFB.

[@AndreMartens-y5h]

I have a searchlight signal a h5

[@terrywebb8636]

Mr. Clay why are the caboose trucks different from freight?

[@MarkClayMcGowan]

Just guessing here, because I don't know, but I'd say maybe they don't have to support as much weight?

[@tinindian9543]

A +++++

[@jonathanhusner8756]

Hey mark do a thunderstorm video

[@MarkClayMcGowan]

We rarely have them around here, so that's hard to do. I was out of town for this last storm and it didn't get to where I was.

[@johnschultz9023]

It's not really a color position signal. The B&O used the GRS Type U.

[@NS3210]

Many people ask why I stopped railfanning as much as I used to, its simple. Alot of character from the Class 1 RRs of today are almost nonexistent. Alot of the signals, the roster, and even the sounds (Detector Voices, the same 3-4 horns) are all the same, the only way to tell what RR is what is the paint scheme. Even NS are starting to do away with the older CP signs from the SOU days.

[@rogerpenske2411]

Somebody answer the phone!

[@TommyJensen-pl8qz]

the first signal in the video needs cleaning and lubrication

[@MarkClayMcGowan]

It already got it, but thanks for the positive review

[@DM-lg7hk]

Too bad they took alot of the searchlight out like them better

[@MarkClayMcGowan]

The searchlights were good signals, but the LEDs show a far superior aspect without having to be aimed to a point, are easier to maintain and work on, and much less expensive. Thanks for checking it out!

[@paullubliner6221]

@@MarkClayMcGowan NO MARK! The green has a peak wavelength of 505 to 515 nm which is greatly absorbed in fog or misty weather, significantly reducing the range. The red peak wavelength of 635 is too orange for true "Railroad Red" (660 nm) and therefore is sometimes confused with adjacent to the Right of Way traffic lights. They have problems, not a panacea of any kind.

[@MarkClayMcGowan]

I have never heard a complaint from train crews, and if it were a true issue, the FRA would never have okayed them. They're certainly better to work with for we signal guys as there's never any doubt as to what color a signal is during a cutover or working a problem.

[@paullubliner6221]

@@MarkClayMcGowan Then you need to ask the Hogheads I know. As for the FRA, do realize they also were "ok" with East Palestine, Ohio's outcome as well, never mind 10 miles worth of active hot box detectors. What I said about the 505-515nm visible absorption by heavily moist air is indeed correct.

[@MarkClayMcGowan]

@@paullubliner6221 first off, I don't know the hogheads (which no one calls them any more) you know, so I can ask them nothing. I only know the ones I know, and the ones to whom I've spoken about it, like them better, even in the San Joaquin Valley's famous Tule Fog. Second, hot box detectors don't fall under the purview of the FRA as they are not part of the signal system or track structure. What the FRA signed off on was that the crew operated the train exactly as they should have, and the signals and track had nothing to do with any of it. Every HBD worked as intended as set up by the NS.

[@edwardgray154]

as a railroad man i still cant figure why most class 1 roads have gone to those vader type signals i worked for conrali and they did the same thing, not only that they did away with most way side signals and switched to cab signals which i never trusted. as i have seen them fail many times.

[@MarkClayMcGowan]

Here are a few of the reasons LED signals replaced searchlight signals. Searchlights had to be precisely aimed. LEDs are good if they're pointed in the general direction. They relied on a system of a reflector and two magnifiers which made them susceptible to damage as well as "phantom" aspects if the sun was just right (which I encountered on three occasions). LEDs are simply bright bulbs. The searchlight mechanism had to be tested quarterly for movement, and bi annually for operational values, both of which were VERY time consuming. LEDs have no moving parts. Searchlights were HEAVY, necessitating a boom or other lifting device should they need to be changed. Three headed LED signal can be changed with a few guys and a good rope. Searchlights were expensive (the mechanism alone was around $2,000), LEDs aren't cheap, but their cost is made up for in ease of maintenance. Thanks for checking it out!