a lot of automobiles have switched to using LED clusters for head and taillights. Is it concievavbly that locomotives could head on the same direction once the LEDs become cheap enough? The only real advantage cpuld be a minuscule reduction in maintenance and brighter head, marker ditch lights.
Modeling the Pennsylvania Railroad in N Scale.
www.prr-nscale.blogspot.com
Amtrak uses led headlights/ditchlights in their new electrics.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
GP-9_Man11786Is it [conceivable] that locomotives could head on the same direction once the LEDs become cheap enough?
I had thought the move toward LED lighting was well advanced, both in 'new build' locomotives (the ACS-64s for an immediate example have them) and in the retrofit market.
There are advantages other than first cost, and I suspect the reduction in maintenance cost is better than 'minuscule' especially including the reduction in cost to remediate a conventional headlight that has gone out 'on the road' and has to be replaced under applicable rules.
It has probably taken some time for the 'cheaper' LEDs and support circuitry to make it into the 64 to 72V, heavier-shock railroad world effectively. Remember that historical issues with LED high-power lighting involve the considerable heat-sink requirements and the inherent low resistance to voltage spikes -- but once solutions to these have been costed down, or a price and reliability point reached which outperforms traditional (and often costed-down) solutions -- expect to see it across the board.
One interesting issue with LED main lighting is that some of it is multiplexed, meaning that one 'driver' circuit works for many physical light-emitting diodes with some persistence-of-vision and internal phosphors making up the difference in continuous light. This shows up dramatically in digital photography of some of the units equipped with these lights. Digital photography can have extremely fast effective shutter speed (with the additional 'exposure time' involving post-processing and storage of the captured image) and it's not uncommon to see pictures in which multiplexed lit LEDs have not registered as 'on.' I have been waiting with some amusement to see these sent to railroads as evidence of 'rules violation' or brought up in court by ambitious attorneys eager to show railroad 'negligence'. There are probably some people who would believe the evidence of their lying eyes and not want to hear the "excuses"...
One other advantage of cheap LED lighting is that it can be applied in places other than 'traditional' light housings or positions. Combined with a certain amount of active or steered focus, it may be possible to provide a large amount of "visual stimulus" in addition to just head and ditch lights, or actively provide high-intensity projection or images in the 'skin' of the locomotive; some of the interesting possibilities seen in LED 'building lighting' and graphics have definite application in railroading.
A drawback of LED's is they don't generate enough heat to melt snow and would need constant cleaning when used in such conditions.
Never too old to have a happy childhood!
BaltACD A drawback of LED's is they don't generate enough heat to melt snow and would need constant cleaning when used in such conditions.
IIRC, some automotive LED fixtures actually include heaters for that very reason.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
The city of LaGrange Ga is replacing mercury vapor & metal halide street lights with LEDs. The LEDs are very aimable and tend to place much more light on the street. we notice that the lights across street ( either way ) are pointed more toward us but once in the opposing lane for left turns they are very much brighter, The aiming certainly may be important. No one has indicated how the city is disposing the now surplus fixtures and to a lesser extent bulbs that still have life ? l
zugmann Amtrak uses led headlights/ditchlights in their new electrics.
Some of the newer diesels seem to be using LED lighting on steps, and some of the 'other' lighting around the sides (manway(?) areas of newer locomotives.
Also have not noticed any of LED style on the headlamps or ditch lights.
I also wonder if itwill. Used in newer passenger cars. That could be a substantial reduction in HEP needed.
In Australia, Pacific National, one of the two biggest operators has refitted their main intermodal units (120 units altogether) with full LED lighting at their 15 year overhauls.
This includes headlights, marker lights and flashing ditch lights.
The blue white headlights show up more clearly at greater distances, but I can't say what the view from the cab is like at night.
The LEDs are fitted into standard casings and are the same size as the sealed beams they replace. They are a dense matrix of hexagonal shape with maybe 50-100 individual LEDs. Two are fitted, like sealed beams.
The ditch lights consist of six larger LED units each arranged in a circle, again, fitted in the usual incandescent lamp casings.
Marker lights are similar to the headlights but smaller, and come in red and white, of course.
Many locomotives have been built with, or have had LED marker lamps fitted at overhaul.
The preserved Beyer-Garratt 6029 has LED headlights and ditch lights. The ditch lights, not being original, are quite small to reduce the impact in appearance, particularly when out od use. Since the locomotive is overall glossy black, the lights are important visual aids.
The Sydney "Waratah" trains (78 eight car sets) have full LED lighting inside and out. However, the power required for propulsion and air conditioning mean that there is little net power reduction. The long life of the LEDs is a cost reduction, maily in manpower to replace bulbs and tubes.
M636C
FRA Locomotive lighting regulations
https://www.law.cornell.edu/cfr/text/49/229.125
M636CThe blue white headlights show up more clearly at greater distances, but I can't say what the view from the cab is like at night.
I put LED DRLs on my truck. They're bright to look at, but you wouldn't want to drive with them at night.
OTOH, the LED headlights on our new fire pumper are plenty bright for driving, and aren't as blue as many of the LEDs you see. Given the proper optics, I suspect they'd be just fine on a locomotive. I have seen step lights, etc.
We're starting to replace some of the light bulbs in our passenger cars with LEDs. There aren't enough yet to make a major difference in HEP load, but time will change that.
BaltACD FRA Locomotive lighting regulations https://www.law.cornell.edu/cfr/text/49/229.125
There is nothing in the regulations that suggest the type of technology to be used. However, I'm not sure how you would dim an LED headlight - possibly just use a secondary light of lower power.
What did strike me was the regulations say nothing about how the headlight performs as a light for the operator. They are only concerned with how the light appears to those outside the train.
In Australia, the ditch lights flash automatically when the horn is sounded.
The recent Chinese SDA-1 type locomotives in Australia also flash the ditch lights when they are powered up and when the brakes are released, handy for employees in yards and depots. They have LED ditch lights but incandescent headlights.
M636CThere is nothing in the regulations that suggest the type of technology to be used. However, I'm not sure how you would dim an LED headlight - possibly just use a secondary light of lower power.
The secondary diode core(s) approach will certainly work,, and it has the secondary advantage that the 'dim' can be at a different reflector focus and/or aimed downward to carry well but provide less 'dazzle' to oncoming crews. It also ought to be compatible with existing switch arrangements.
However, I think it's probably at least as good to dim by modulating the voltage to the diodes at very high frequency, similar to the way older triac dimmers worked. The net result is not only that fewer lumens are emitted at the diode in operation, but that the diode is not powered a considerable portion of the time, so the 'net' illumination is less.
M636C BaltACD FRA Locomotive lighting regulations https://www.law.cornell.edu/cfr/text/49/229.125 There is nothing in the regulations that suggest the type of technology to be used. However, I'm not sure how you would dim an LED headlight - possibly just use a secondary light of lower power. What did strike me was the regulations say nothing about how the headlight performs as a light for the operator. They are only concerned with how the light appears to those outside the train. In Australia, the ditch lights flash automatically when the horn is sounded. The recent Chinese SDA-1 type locomotives in Australia also flash the ditch lights when they are powered up and when the brakes are released, handy for employees in yards and depots. They have LED ditch lights but incandescent headlights. M636C
The regulations mention incandescent and halogen lamps as well as specific wattages. They make no mention of LED's.
BaltACD The regulations mention incandescent and halogen lamps as well as specific wattages. They make no mention of LED's.
The standard indicates that the quoted lamps meet the requirements of the standard.
It does not suggest that the quoted lamps are the only acceptable solution.
If a manufacturer offered LED lamps that could demonstrably meet the standard as laid out, I'm sure they would be accepted.
The SAE had similar standards for automobile headlights which has not prevented the proliferation of LED lights on private automobiles.
I expect that the standard was written to allow for future developments, hence the wording of the standard and the statement that certain existing lamps meet the standard.
While voltages and watt measurements are quoted in the examples, they are notably absent in the performance definition above.
As I've indicated, LED headlights meeting the standards used in the USA are already in use elsewhere, and apparently, on the Amtrak Siemens electric locomotives. If LEDs are acceptable for rail signal lamps, they will soon be adopted for headlights.
M636CThe SAE had similar standards for automobile headlights which has not prevented the proliferation of LED lights on private automobiles.
But applicable laws, for many years, mandated 'sealed beam' lights without glass covers over them, specifically to get around excuses for using 'bulb in reflector' technologies which at the time produced inferior light, which had the effect of keeping clearly-better technologies -- Cibie lights, in particular -- from being "legal". The 1965 Chrysler Imperial had glass plates over the headlights as designed (yes, how much better a designer Engel was compared to Exner!) but in many jurisdictions those were not allowed (and subsequent designs deleted them). New laws had to be passed to permit the halogen bulbs in permanent 'streamlined' enclosures (9000 series, etc.) and by extension xenon HIDs, and some of the associated light intensity and pattern requirements of state laws then became more of a limitation (hence the otherwise-inexplicable behavior of the high and low beams on 1994-era GMC trucks).
I do note that the FRA regulations -- probably because they are nominally concerned with 'safety' and that not being the safety of crews because they are better able to see in front of them -- are more concerned with the effect of the light on those outside the cab. I do find it strange that the standard, as BartACD describes it, apparently goes into detail with bulb type and wattage rather than defining compliance being thus-and-so an illumination (with an appropriate color temperature) at thus-and-so a distance in thus-and-so a pattern (as is incorporated, sometimes a bit defectively from an engineer's point of view, in motor vehicle laws). I would think this is more a general guide to railroads as what to use in existing locomotives than a necessary choice of hardware. We obviously know LED headlights are FRA legal because they are currently in use on the general system of transportation.
OvermodI do find it strange that the standard, as BaltACD describes it, apparently goes into detail with bulb type and wattage rather than defining compliance being thus-and-so an illumination (with an appropriate color temperature) at thus-and-so a distance in thus-and-so a pattern (as is incorporated, sometimes a bit defectively from an engineer's point of view, in motor vehicle laws).
Actually, there is a specific standard given:
(a) Each lead locomotive used in road service shall illuminate its headlight while the locomotive is in use. When illuminated, the headlight shall produce a peak intensity of at least 200,000 candela and produce at least 3,000 candela at an angle of 7.5 degrees and at least 400 candela at an angle of 20 degrees from the centerline of the locomotive when the light is aimed parallel to the tracks.
Recall that at one point there were headlight systems made up of five or six smaller lamps which fit into the form factor of the original headlights they replaced.
If those multi-bulb lights meet the intensity standard, I would surmise they would be legal today. The question would be if the loss of one lamp of the several would cause the system to fall below minimums, thus falling into the "failed" camp.
In the meantime, if an LED headlight can meet the intensity standards, I see no reason it could not be used. I would surmise that it would be up to the manufacturer or the railroad to prove that the "non-standard" light met that standard.
tree68Recall that at one point there were headlight systems made up of five or six smaller lamps which fit into the form factor of the original headlights they replaced.
All the ones that had seven (six in a hexagon and one in the middle) were, I thought, built that way; all the ones I remember having seen were streamlined cab units, and I presumed when I was very young and first saw an example that the 'idea' was to have an enormous illumination directed forward, a bit like Euclid's "light cannon" idea.
If that setup was in fact retrofitted to a unit that originally had a reflector bulb, I'd like to learn the details. This is one of those exotic areas like the UP's/C&NW's upward-facing light that deserves better 'scholarly attention'.
Dual aimable sealed-beams in the space of an ordinary headlight,, of course, are legion (behind the original glass, as in B&O E units, or in the headlight frame, as on the PRR T1, or in a special bolt-on cover, as on the NYC Niagara and some others), these providing the over-the-road redundancy and presumably the better aiming capability in the original Pyle-National patent for the 'conversion'. But I think it is very rare to find more than two, and where an additional 'clear headlight bulb' is used, it's in an explicitly oscillating light either as a different kind of warning or, as KCS used it, to spotlight areas outside the main headlight beam coverage.
If those multi-bulb lights meet the intensity standard, I would surmise they would be legal today.
There's little chance they wouldn't!
The question would be if the loss of one lamp of the several would cause the system to fall below minimums, thus falling into the "failed" camp.
And this, indeed, is where I think the issue comes in. It was my distinct understanding (although I cannot produce a reference) that the reason SP gave up on its 'light shows' was that the Feds required any bulb in any light, when it burned out, to be replaced, whether it was "safety critical" or not (the given reasoning ... this being from memory after several decades, so don't hold me to it ... being that if a railroad provided a light, it had to be for some safety or service-related reason, and hence it had to be maintained strictly). What was a bit sad was that just removing the bulbs from the now-disabled lights wasn't 'enough' -- they had to be physically removed or plated over.
It followed (for me at least, at the time) that the seven-light system would have to be serviced every time one of its internal bulbs burned out, and it would be reasonably unlikely that two or more would go out within the required response time, so the cost of the system would be relatively large for a given range of individual-bulb longevity. That would quickly sour many railroads on the idea of providing it, particularly after the early evidence that much of the additional 'high-speed alert lighting' approaches didn't produce much improvement in practice.
tree68In the meantime, if an LED headlight can meet the intensity standards, I see no reason it could not be used. I would surmise that it would be up to the manufacturer or the railroad to prove that the "non-standard" light met that standard.
Or they could get a waiver if the law hasn't caught up to the technology.
Overmod But I think it is very rare to find more than two, and where an additional 'clear headlight bulb' is used, it's in an explicitly oscillating light either as a different kind of warning or, as KCS used it, to spotlight areas outside the main headlight beam coverage.
MILW seemed to like using 4 in their electrics.
All the new locomotives CN purchases now come with a mix of LEDs and incandescents. On the outside of the unit, ground, step, walkway and numberboard lights are LED but the headlights/ditchlights/markers are incandescent (the reason being that it SNOWS up here and they have to melt ice). Inside the cab most lights are LEDs, but the desk lights for both the Conductor and Engineer are incandescent. They also don't seem to be replacing any bulbs on older units with LEDs, instead sticking with incandescents.
Greetings from Alberta
-an Articulate Malcontent
I realised that I could count the LEDs in the Australian LED headlights.
Remember that these sit in standard AAR type dual sealed beam casings, so the outer diameter is slightly less than the standard sealed beams.
When the locomotive is at a sufficient angle to the camera lens the LEDs appear as small white circles. Looking straight at the headlight from ahead, it appears as a very bright single light, of course.
There are 36 LED elements arranged in a grid of 37 with the central point left blank..
So the lamp appears as a hexagon arranged in rows of LEDs each row offset by half an element:
4+5+6+7+6+5+4 (with the middle spot in the "7" blank.)
The ditch lights are quite different, being just a circle of six elements, which look individually larger than those in the headlight.
Going to work last night, police had a car pulled over to the side of our 2 lane road in the opposing direction - It has a LED light bar on the roof - the light bar was displaying flashing red & blue to the rear and had a solid white display to it's front - from a couple of hundreds away that white display appeared to to be about 2 feet high for the width of the police car and was ABSOLUTELY BLINDING to on coming traffic. It was just the normal 4 inch or so high light bar with white LED's to the vehicles front.
My observations, Police & Fire Depts that are using LED light bars need to tone down the power of the displays after dark - they are absolutely blinding and I feel can cause accidents because of blinding oncoming drivers
Here is an interesting article that is critical of LED street lighting because of alleged health effects:
http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/medical-group-warns-health-threats-white-led-street-lights
BaltACD Going to work last night, police had a car pulled over to the side of our 2 lane road in the opposing direction - It has a LED light bar on the roof - the light bar was displaying flashing red & blue to the rear and had a solid white display to it's front - from a couple of hundreds away that white display appeared to to be about 2 feet high for the width of the police car and was ABSOLUTELY BLINDING to on coming traffic. It was just the normal 4 inch or so high light bar with white LED's to the vehicles front. My observations, Police & Fire Depts that are using LED light bars need to tone down the power of the displays after dark - they are absolutely blinding and I feel can cause accidents because of blinding oncoming drivers
One reason the LED locomotive headlights are so effective is that they create a bigger "patch" of bright light to the viewer than the incandescent bulbs they replace.
Interestingly, this effect does not appear as great in digital photos of the trains, suggesting that the difference is in the way the eye sees the light, compared to the CMOS sensor in the camera.
Unlike the old incandescent lights, you can't just apply a dimmer to reduce the voltage. It may be necessary to arrange the LED lights in such a way that 1/3 or 2/3 of the array is turned off to get the appropriated dimmed effect as seen by the human eye.
In the case of the police car, the light is intended to illuminate the scene, particularly a stopped vehicle, in front of the police car. A very bright light would mean less chance of the police officer missing some action by the stopped driver or other person of interest that might put his life at risk, so the effect on other road users might be regarded as secondary to the safety of the police officer.
An alternative with a lower power LED and a very high power focussed spotlight aimed at the driver's side of the vehicle ahead might be a solution that reduces the effect on oncoming cars.
BaltACDMy observations, Police & Fire Depts that are using LED light bars need to tone down the power of the displays after dark - they are absolutely blinding and I feel can cause accidents because of blinding oncoming drivers.
Heck - that's a problem with regular incandescent headlights, much less LEDs.
We (fire) prefer to kill the headlights on scene so oncoming drivers can see our people who are trying to control traffic.
I think a large part of the problem with the LEDs is the different color. As I noted earlier, my DRLs look bright, but you can't drive with them.
That said - some early LED and strobe light bars had a "night" mode. Haven't seen much of that lately. Units used on limited access roads oftimes can kill the front lights, more to prevent "lookie-loo" issues in the oncoming lanes than anything else.
These days, the cops need to be able to see what's going on in that car - it's getting more and more dangerous.
Something I have seen is full width LED bars on civilian vehicles. They are all "white" and are intended as off-road driving lights. I wasn't aware of any police agencies using them, but I could be wrong.
The problem with LEDs is that they don't really give off "white light". For that matter, there is no such thing as "white light"! Light is a continuous spectrum of electromagnetic energy that the biological eye can perceive. That perception is based on 3 types of color sensors on the retina of the eye that detect broad bandwidths that are in general "Red", "Green" and "Blue". It is the brain that combines that perception to say what "color" is present.
LED lights give off only narrow bandwidths of electromagnetic energy, generally in what the eye/brain perceives as either "Red", "Green" or "Blue", depending on the particular doping used to produce the particular LED. White LEDs are just 3 emitters, one in each of the 3 colors, arranged so close together that the eye cannot differentiate them and only sees a single point of “White” light.
BUT... when those same proportions shine on an object (or objects), only the colors that are not absorbed by the object(s) reflect and thus only those colors can be perceived... so if the object(s) is "Yellow" and there is NO "Yellow" coming from the light source (assuming the LED is the only source) that can be reflected, the object(s) will only appear as dark (i.e.: black, no light reflected).
Now, compare shining a broad spectrum incandescent light on a general outdoor street scene. Gray concrete, brown dirt, Dark Green foliage, and other random color objects.
With the incandescent light there will be roughly equal amounts of near infrared light, as well as pink, red, orange, yellow, green, blue, indigo, violet, near ultra-violet, so any object that reflects any color will be seen.
But if that same scene is illuminated by a “White” LED, since the LED only provides Red, Green and Blue light only those objects that reflect those specific frequencies of light will be seen as bright. EVERYTHING else will be dark.
Gray concrete will only reflect the "Red", "Green" and "Blue" light available, but no "Yellow" or "Orange" or any other color, so it will appear darker than if it were illuminated by a broad spectrum incandescent lamp.
To get the same "illumination" to be perceived by the eye, there has to be immense amounts of "Red", "Green" and "Blue" to produce a 'bright' scene.
Technology is advancing and newer LEDs are getting better at providing a broader spectrum of “Red”, “Green” and “Blue”, but they still do not provide as broad a spectrum as a simple incandescent light.
Semper Vaporo
Pkgs.
Not sure you're spot on there SV, although you're very close.
Yellow light is a combination of green and red. Purple is red and blue, and green and blue creates cyan. But a yellow LED doesn't necessarily have a red and a green element (more later).
I've "mixed" colors using theater lighting - our high school theater had dimmable "border" lights hanging from the grid iron - in red, blue, and green. Get the right intensity of each color and what you see on stage is, indeed, white, or whatever color you're looking for.
Given a lesser intensity of red and green in an LED headlight, you will get the bluish color. But that's a choice of the manufacturers. The headlights on our new pumper are LED, and they look pretty "neutral" to me.
Another consideration is that many (if not most) LEDs get their color by "doping," not by having three elements side-by-side. By varying the composition of the materials (and the materials themselves) within the LED, you get different colors.
Your LED TV, on the other hand, does create colors using those three primary colors - you can see that with a magnifying glass.
I'm pretty sure doping is how the colors of the LED light bulbs at the home improvement store are created.
Tree: Yes, you perceive "yellow" if you see equal amounts of "Red" and "Green", but something that reflects only the frequency that is between "Red" and "Green" (called "yellow") will not reflect either "Red" or "Green" and you will not see either "Red" or "Green" with your eye. i.e: you will see just black.
I no longer have access to the equipment, but if you get a collumnating lens system and shine a white incandescent lamp through it and that then through a prism to break the beam into the light spectrum (rainbow), and you should see a relatively uniform spread of the colors, including "orange" and "yellow" and all the others.
Do the same with a White LED and you will just see three narrow bands of the colors that the LED is emitting, with blank areas between them... i.e.: no "orange", no "yellow" and no "violet" like you see from the incandescent light source.
If there is no "yellow" light, then yellow objects will be dark. If the yellow object does reflect a wee bit of "Red" and a wee bit of "Green" then you will see a dark "yellow" object... If it does not reflect any "Green" then you will see a dark "Red" object, not a "yellow" one.
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