LOWERS QUADRANT SEMAPHORES

[Loco2124]

If lower Quadrant semaphores were used to display only 2 aspects, why do they have 3 spectacles?

[Overmod]

The spectacle is part of the counterbalance.  Rather than have two different sizes of parts (including motor drives) it might make better sense to 'standardize' on three aspect plates and simply blank the unused aspect position or leave its glass out.

[tree68]

Loco2124

If lower Quadrant semaphores were used to display only 2 aspects, why do they have 3 spectacles?

Lower quadrant semaphores could display all three aspects.  Depends on what the railroad wanted...

 

[Overmod]

There is another point here, though, which is that a 45-degree mechanism couldn't safely display three aspects on a lower-quadrant semaphore.  If the power goes out the blade will might fall under gravity to the same indication as full,and that's as bad as having lunar white, the color of fallen-out glass roundel, being full speed ahead...

For this, if you want three aspects, use a 30-degree increment head.  Horizontal is still stop, you have distinguishable levels at the two angles... and straight down is still 'most restrictive you can get' -- put a red in that fourth position if you want nighttime redundancy.

[jeffhergert]

Overmod

There is another point here, though, which is that a 45-degree mechanism couldn't safely display three aspects on a lower-quadrant semaphore.  If the power goes out the blade will fall under gravity to the same indication as full,and that's as bad as having lunar white, the color of fallen-out glass roundel, being full speed ahead...

For this, if you want three aspects, use a 30-degree increment head.  Horizontal is still stop, you have distinguishable levels at the two angles... and straight down is still 'most restrictive you can get' -- put a red in that fourth position if you want nighttime redundancy.

 

I always thought that lower quadrant semaphores were counter balanced to go to horizontal if something fails. 

Some lower quadrant semaphore train order signals had clear with the blade at or near vertical.

Jeff

[Overmod]

jeffhergert

I always thought that lower quadrant semaphores were counterbalanced to go to horizontal if something fails

They certainly ought to be; the question being whether you can trust the counterbalancing always working.  As a general rule, you want 'failure' either to display the most restrictive aspect or to result in something 'undefined' in operation that a system can rapidly and unambiguously recognize (the latter being a principle of computer binary logic, where the states are two different voltages or other quantities, not 'on' and 'off' as some explanatory books describe it.

I'd be nervous even about a train-order signal using lower-quadrant vertical as 'proceed' but as you noted, it's their sandbox.

[timz]

That's a question -- were single-blade lower-quad automatic block signals always two-position, not three? What objection is there to 0-45-90 counterweighted blades?

(By the way: who used 0-90 lower-quad blades, besides N&W?)

[Overmod]

While we're here, who used 0-30-60 lower-quadrant aspects?

[jeffhergert]

Here's a picture, first one of the article, showing a lower quadrant with red, yellow, and green aspects on the SP.

 Railroad Signals: Search Lights, CPL's, And Semaphores (american-rails.com)

Jeff

[Overmod]

Thanks, Jeff.

[timz]

The SP single-blade semaphore has two aspects. The three lenses are just for show.

[Overmod]

timz

The SP single-blade semaphore has two aspects. The three lenses are just for show.

You miss the point.  In the picture, look at the left-hand and right-hand spectacle positions over the lamp relative to the blade angle.  I asked about 30-60-90 mechanisms and since these are obviously spectacles corresponding to those angles it would be fairly safe to assume the mechanism parts are, too.

(Yes, technically that should probably be a 90-60-30 in lower-quadrant use, but it's the incremental angle in either case that's significant)

I can't imagine these were designed with three positions for lenses without corresponding 'mechanism' for those positions.  That isn't to say SP used all of them; it's not uncommon to find spectacle positions 'blanked' with plates where particular railroads did not use corresponding positions.  But there is no position on these spectacles for an aspect corresponding to 90 degrees with the given blade attachment style, although I think I have seen plates with four openings in a couple of places (don't ask me where; I'm not a semaphore guy).

[BaltACD]

Overmod

 

timz

The SP single-blade semaphore has two aspects. The three lenses are just for show. 

You miss the point.  In the picture, look at the left-hand and right-hand spectacle positions over the lamp relative to the blade angle.  I asked about 30-60-90 mechanisms and since these are obviously spectacles corresponding to those angles it would be fairly safe to assume the mechanism parts are, too. 

(Yes, technically that should probably be a 90-60-30 in lower-quadrant use, but it's the incremental angle in either case that's significant)

Seemingly all TV, both over the air and cable channels, have synchronized their commercial minutes so channel surfers go from one commercial on a channel to another commercial on another channel; with the hopes that they will return to their original channel as they will be unable to find anything more interesting.  Somehow this even tends to work on sporting events when you would think the 'breaks in the action' would generate less than predictable commercial slots.

When I was a season ticket holder of the BALTIMORE COLTS, there was a individual that would walk on the field in what appeared to be a fireman's duty coat - he was the identifier to the game's referee that a commercial was being taken and for play to be held up.  In the September & October games it was a minor inconvience.  In the bitter cold and winds of November and December games one wanted to get him off the field post haste.

[Overmod]

Balt, doesn't this post go in the 'Then and now' thread???

[Loco2124]

I have read about 3 position LQS having a fully vertical position that could sometimes be hard to read blending in with the mast. But on a 30-60-90 configuration, couldn't the 30 and 60 be confused as well?

 

[Loco2124]

I have seen LQS with 2 red spectacles and one yellow...

[Fred M Cain]

jeffhergert

Here's a picture, first one of the article, showing a lower quadrant with red, yellow, and green aspects on the SP.

 Railroad Signals: Search Lights, CPL's, And Semaphores (american-rails.com)

Jeff

 

Jeff,

 

Where?  I'm not seeing that.  I feel like I'm pretty familiar with SP's semaphores 'cause they had 'em in Phoenix when I was living there as a high school kid in the late 1960s.  The red flags had one green lens and two red lenses while the yellow flags had one green lens and two amber lenses.

 

If you saw a picture of an SP semaphore with a green, amber and red lens all on one blade, I'd tend to suspect that the quality of the picture might be questionable but I can't prove that.

 

This always puzzled me as to why as well.  I had always just assumed that while semaphores change position rather slowly, they wanted to have as little of a gap as possible when changing from clear to a more restrictive aspect.  If that middle lense were not there the signal would go dark at night while the blade was changing position.  That's my guess for what it's worth.

 

Does anybody know where we can find a retired SPT Co. signal maintainer?  They might know.

 

By the way, I did once read somewhere that some early predecessor companies to the New Haven Railroad used three-position lower quadrant semaphores but that was long, long ago and I think they might've been manually operated from "Armstrong" levers.

 

Regards,

FMC

[timz]

Far as anyone knows, no US railroad used block-signal semaphores showing three aspects at 30-degree increments of blade angle. Lower-quadrant blades were almost always two-position, 60 degrees apart; the exception could be two-position, 90 degrees apart.

Dunno if any US railroad tried 0-45-90 lower-quadrant semaphores as block signals.

[Fred M Cain]

timz

<SNIP>

Dunno if any US railroad tried 0-45-90 lower-quadrant semaphores as block signals.

 

 

Yes, I think so.  I recall seeing some very old photographs taken in New England showing blades like that on absolute signals at junctions.  But they weren't really "Block" signals since they were controlled by Armstrong levers at junctions.

 

I'll have to ask on the New Haven Railroad forum to see if anyone can verify this for sure.

 

Regards,

FMC

[Overmod]

Fred M Cain

If you saw a picture of an SP semaphore with a green, amber and red lens all on one blade, I'd tend to suspect that the quality of the picture might be questionable but I can't prove that.

Upon actually looking into this, the 'middle' lenses were indeed made as red on two-position lower-quadrant semaphores in American practice; this was called the 'Continuous Light Spectacle' and was supposed to keep the 'most restrictive' aspect visible if snow or ice or some other agency overbalanced the blade.

That middle aspect in the right-side head in the picture sure does look like a different, and more amber, color though... enlarge the picture and see.

It does appear there were 45-90 LQ heads made, with one of the last of them apparently in Memphis.  I do not have pictures but knowing they existed will help with the search.

 

[timz]

Never occurred to me to wonder about that -- what color was the middle lens on SP semaphores? Looks yellow on signal 5077 -- was it always red on interlocking semaphores? And never red on automatics? Dunno.

[Fred M Cain]

Overmod

Upon actually looking into this, the 'middle' lenses were indeed made as red; this was called the 'Continuous Light Spectacle' and was supposed to keep the 'most restrictive' aspect visible if snow or ice or some other agency overbalanced the blade.

Overmod,

 That, I believe, is a good explanation possibly the best one we can get.

Another piece of semaphore trivia I could share has to do with the fact that I was once always puzzled as to WHY the SP would use these semaphores in the first place.  I mean, they had electric motors, right?  And electric lights, right? So with that technology in place, why didn’t they just use color light signals?

 

I got my answer in the late 1980s while riding Amtrak’s Sunset Limited westbound across West Texas.  There was an elderly SPT Co. conductor on board nearing retirement telling me stories about his career so I decided to pose this question to him.  His answer was both very logical and at the same time complicated.

 

He told me that they used semaphores, “because they had trouble generating a light that was bright enough to be seen in the daytime”.

 

Realize, that prior to around 1935 or so, there was no electric power in much of the wide-open West outside of towns and cities.  So these signals were all powered by batteries.  The electric lamps were both approach-lit and of very low wattage so as to not drain the batteries too fast but the low-wattage feature made them nearly impossible to be seen during daylight hours especially with the bright sunshine in the desert.

 

The blade movement was as ingenious as it was complicated.  I think it would take too long for me to try and explain that here and probably you can find that explained somewhere else.

 

The conductor told me that they employed signal maintainers that had to regularly change out the lead-acid batteries and take them back to be recharged.  Then if it went too long, the blades would start “pumping”.

 

It was a most interesting piece of railroading trivia.  Now they’re all gone.  But I’ll tell you what.  On a bright summer’s day in Arizona, you could see a semaphore indication farther away than you can see the indication of these “modern” lights they’re using nowadays.  The thing is, though, that with all this new technology, wayside signals are just not as important as they were back in the steam days.

 

Regards,

Fred M. Cain

[Overmod]

timz

was it always red on interlocking semaphores? And never red on automatics?

One reference I saw in passing indicated that the 'continuous aspect' was appropriately 'double yellow' on distant signals and 'double red' on home signals; this would jibe with what Fred noted about yellow and red blades.

[Overmod]

A great breakthrough with color lights was the two-lens 'searchlight' which reduced the 'color' lens to small dimensions and allowed good projector optics without loss.  I am not surprised SP adopted these... for the most part, unsurprisingly, approach-lit

Suspect those were not lead-acid, but "Edison" nickel-iron storage batteries, at least in that era.

[Fred M Cain]

Overmod

A great breakthrough with color lights was the two-lens 'searchlight' which reduced the 'color' lens to small dimensions and allowed good projector optics without loss.  I am not surprised SP adopted these...

Suspect those were not lead-acid, but "Edison" nickel-iron storage batteries.

 

I thought I saw lead-acid batteries at some point but maybe I'm remembering that from somewhere else.  Whatever they were I was told they had to be recharged.  I don't believe they had solar panels yet.

As for the searchlights, I have been told and I think it's true that they operated much in the same way that the searchlights did except there was no blade.  As you said, they were "focused" so that they could be seen in the daytime at a distance.

I took a cab ride up the San Joaquin Valley in the early nineties when the BNSF was replacing the old AT&SF searchlights with new three-color "hooded" signals.

I asked the conductor why they were replacing them and he told me that "Well, you see, they getting rid of the signals that you can see and putting in new ones that you can't see".  He was sort of joking but I saw that he was right.  Some of the newer signals were very hard to see. At one point, I heard the engineer say, "I can't make out this signal" and his conductor told him "I've got it.  It's green".

Regards,

FMC

[Fred M Cain]

As long as we’re at it, here is a nice shot of a pair of SPT Co. semaphores shot through the cab window.  I believe, if I’m not mistaken, that this was shot east of Tucson on the double-track line.  A few of these blades on the former EP&SW right of way actually survived up until the time of the “You Pee” takeover.

 

http://southernpacificrailroad.blogspot.com/2010/11/

 

But here is something REALLY fun and RARE!  Someone shot a video of a cab ride between Yuma and Phoenix in 1991.  There are a lot of nice scenes of SP’s classic searchlight signals and a few blades that actually survived well into the ‘90s east of Wellton.  They were still functioning up until the SP took the line out of service at about 1995 or ’96.

 

Here it is.  Have fun! :

 

https://www.youtube.com/watch?v=_kGDeOnA1tg

 

Regards,

Fred M. Cain

[Erik_Mag]

Overmod

Suspect those were not lead-acid, but "Edison" nickel-iron storage batteries, at least in that era.

I seem to recall running across several references to lead acid batteries being used for signalling. Unlike car lighting batteries, the signal batteries would only have to be moved for charging. Charging of the signal batteries would have been more controlled than charging of car lighting batteries. I believe lead acid batteries have a flatter discharge characteristic than nickel-iron batteries and possibly a lower self discharge rate.

Interesting fact: The first power semiconductors were the copper oxide rectifiers used for charging signal batteries.

[jeffhergert]

Here's a video on how a searchlight signal works.  The signal in the video is a "pot" or "dwarf" signal, one that's at ground level, but the tall ones work the same way.

 SLO Railroad Museum (slorrm.com) 

I don't agree that waysides aren't has important anymore.  That new technology (PTC) still fails.    

A lot of how well a signal can be seen depends on how well it's "aimed" down the tracks.  Keeping vegetation cut back also helps.  The new LED bulbs are brighter than incandescent bulbs, but don't put out the heat that can keep the light clear of snow buildup during winter storms.  Incandescent bulbs on signals with approach lighting also have problems because they aren't on to keep snow from building up or on long enough to melt any accumulated snow.

Green always seems to be the hardest color to see during daytime.  We have a saying, "If it can't be seen, it must be green."  That's from when we were approaching a wayside signal with a clear aspect on the cab signal.

Jeff 

 

[tree68]

Here's a YouTube video that shows the color mechanism in one brand of searchlight signals.  Credit the YouTuber.

https://www.youtube.com/watch?v=rMrCkOG8cLw

 

[Overmod]

Here's a drawing showing the cross-section of the mechanism with the rough path of the beam dotted in:

https://www.railroadsignals.us/signals/searchlights/USSguts2doublet.jpg