LED-lit signals?

[Bergie]

In our area, traditional stop lights lit by bulbs are being replaced by newer assemblies that contain dozens of LEDs (up to 100, I would guess) in place of a single bulb. They are very intense, and from what I've heard, they save the local municipality a lot of money over the course of a year because each uses far less engery. Plus, since the life expectancy is far greater, you also save greatly on maintenance crews who used to be needed to replace burned out bulbs. Those two factors add up to great potential cost savings over the course of time and were probably why we're seeing a move in the new direction, even if it is more costly up front. (And if you've ever been to southeast Wisconsin, you've probably noticed that there's typically 2 stop lights for every 1 that's needed. Some intersections look like an airport runway, so the savings could be huge.)

Anyway, to my question. Does anyone have any knowledge of either these lights, or the LED technology, to know whether these could ever be adapted for railroad signal use? It'd be interesting to know if a new LED signal could be as intense as a traditional bulb-lit type.

I've been pondering this for months, as I wait at stop lights. I've finally taken the time to ask. I hope someone knows.

Bergie

[Randy Stahl]

Keep your eyes open Eric there beginning to appear on many railroads, and your right they are much brighter.
Randy

[locomutt]

Bergie,
I'm not sure about the rail industry;but Police,Fire and EMS are using "LEDs"
in various forms in the vehicle warning lights,and also in certain flashlights.
I would imagine given time,it will come to the railroads.

I'm adding this with "tounge in cheek",but some of us modelers have
been using LEDs in signals for quite awhile.[:)]
I know,not the same thing.

[CShaveRR]

I think we had a thread a while back about these LED signals, how they don't just fail, but slowly dim until they're useless at some point. Of course, we haven't had the required time to see that on any of the traffic lights yet.

As to LEDs in use on the railroad, next time you ride Amtrak into Chicago from Milwaukee (you do do that, don't you?), check out the dwarf signal at the Lake Street Interlocking (oops, Control Point), just before Union Station. One head, three or four colors, hundreds of little LEDs. I think there's a photograph of that one in Brian Solomon's book on railroad signals.

[Anonymous]

QUOTE: Originally posted by Bergie

In our area, traditional stop lights lit by bulbs are being replaced by newer assemblies that contain dozens of LEDs (up to 100, I would guess) in place of a single bulb. They are very intense, and from what I've heard, they save the local municipality a lot of money over the course of a year because each uses far less engery. Plus, since the life expectancy is far greater, you also save greatly on maintenance crews who used to be needed to replace burned out bulbs. Those two factors add up to great potential cost savings over the course of time and were probably why we're seeing a move in the new direction, even if it is more costly up front. (And if you've ever been to southeast Wisconsin, you've probably noticed that there's typically 2 stop lights for every 1 that's needed. Some intersections look like an airport runway, so the savings could be huge.)

Anyway, to my question. Does anyone have any knowledge of either these lights, or the LED technology, to know whether these could ever be adapted for railroad signal use? It'd be interesting to know if a new LED signal could be as intense as a traditional bulb-lit type.

I've been pondering this for months, as I wait at stop lights. I've finally taken the time to ask. I hope someone knows.

Bergie

i think they are using those on grade crossings too.

[Sterling1]

QUOTE: Originally posted by Randy Stahl

Keep your eyes open Eric there beginning to appear on many railroads, and your right they are much brighter.
Randy

How much brighter are they, can they be seen for more distance?

[dldance]

LED signals are not much brighter overall but they are much more directional -- that is more of the light that is emitted is directed in the direction of the observer. There is little need for the large reflector that is behind most incandesent signals. As a result they can be seen from further away - if track geometry allows. Sgnals are a natural application but we are starting to see them in general illumination applications as well for the same reasons - long life, low energy consumption, and low heat emission. I will be a brighter future.

dd

[Anonymous]

On the old BC Rail line that runs through West Vancouver, all the public crossings at grade in ambleside are LEDs.

The signals are huge and when they are on, there's no missing them, they seem to have a much more intense presence.

It's also neat because they have a very definate blink, they don't "fade-to-black" so to speak when they are flshing they are either ON or OFF.

[mudchicken]

Bergie: Look at GRS, Harmon and a few of the others web sites. At the railroad trade shows, the LED fixtures have been prominent for almost 10 years. General Electric uses a searchlight signal in their booth that almost blinds people on the floor.

What is really wild are the applications of some of the smaller vendors for blue lights and marker lights plus induction lighting for pavement crossing approaches and bridges.

[eastside]

Although LED stoplights have a fairly high initial cost, the savings are so substantial and compelling that here in New York City, for example, all the green and red (but not the intermittent yellow, yet) traffic lights, including the walk-don't walk signs, have been replaced. I don't have the numbers at hand, but LEDs use only a few percent of the current that incandescents use. More to the point, the savings in maintenance (bulbs don't have to be replaced) are even larger because LEDs are thought to last for a life time. In a city where there are stoplights on every corner (there must be well over a 100 thousand) the savings in operating costs and maintenance add up to a *lot* of money. They are incredibly bright. Sometimes I've mistaken the green light for an oncoming car light. Indeed the ambient light coming into my apartment is now so bright that I can get enough light to read a book by just leaving the blinds open. It would seem to me that the railroads would benefit even more than cities by adopting this technology.

I have a Lightwave 4000 flashlight (try Googling it). The LEDs are guaranteed for 10,000 hours, but that's probably conservative. It gives off a white light so bright you can't look straight into the lit LED array. LED flashlights are different in that the light is diffuse and not in a concentrated beam. Aside from initial price, my only criticism is that because of the narrow spectral characteristics of current LED technology, the objects lit by them may appear to be very harsh and unflattering. Of course this doesn't matter if the use is only for signalling. During the blackout last year, I left it on all night pointed at the ceiling, lighting the entire room adequately. In another forum, a respondent said he wanted to test the battery life and left his on for 6 weeks before giving up.

[edblysard]

Bergie...
Next time your behind a new Caddy, take a good look at the tail light and stop lights...
LED clusters...

Ed

[mvlandsw]

There is an LED brakeman's lantern available. Some alertors on engines use them in the warning lights. At night they are so bright that they need to be partially blocked from direct view.

[kenneo]

The only possible problem I can see with LED's in signals is their having the candle-power to equal or exceed a standard signal bulb. The FRA has certain standards or visability and as long as these are met, the LED will replace the standard bulbs.

Railroads tend to not change the way they do things unless/until utside forces force them to - such as rules, standards or "the bottem line".

Power use? I have a boat that I use at night a lot, and used to have several deepcycle batteries in addition the the starting battery. I could use up the deepcycle batteries in 18 hours. LED's will take a single battery to over 200 hours. I accidently left the master battery switch on for over 8 days with all the lights on and still had juice in the single deepcycle battery I now use.

[adrianspeeder]

It seems to be a "might as well" thing, as my breaklights burn out, i will change them to LED units. They really do get your attention, as they switch on instant. I already have a hitch cover break light for the diesel, and i know that it shines right into any car windshield makin sure i am noticed.

Adrianspeeder

[M636C]

Most new rail signals in Australia are LED units, just as the road traffic signals are. The rail signals on the Sydney Harbour Bridge, next to the road traffic lanes have been LED units for two years or more. These are visible to most bridge users (if they look). The Bridge and the adjacent underground lines use track occupation indicator lights, visible to track workers, operated from the track circuits and dark when the track is in use. These were small white lights for many years, but are now vertical orange bars made up of LEDs. On the bridge these are mounted on the back of the track signals, and in the tunnels on the tunnel walls.

The Amber LEDs, used in Australia for turnout indications, are a greenish shade quite different from the old lamps.

Peter

[tree68]

LED's can be had in just about any color you want. In addition, you can get a number of "beam widths," just by how the plastic is molded. This would address any such issues the RR may have.

The emergency services are embracing LED's very vigorously, and the vendors are answering with improved optics and reduced prices. Light bars that ran close to $3000 a couple of years ago are about 2/3 that now. And those lights are BRIGHT.

I can get 100 LEDs retail, on line, in a bunch of different colors, for about $80. Imagine the price break for 100,000.

One reason municipalities haven't replaced the amber in stoplights is because they aren't on very much, so limited ROI. Even flashing lights at rural intersections are going LED. New stoplights typically have amber LEDs. Another advantage to LEDs is that if one fails, the rest of the "light" is still on. In many applications they are actually daisy-chained. The "third brake lights" I use as grille flashers in my truck have lost a couple of three LED groups.

An automotive LED "bulb" draws 90 milliamps for a brake light (only 40 ma for tail), or about 1 watt. I'm not sure what the typical RR signal lamp draws, but even going to the 100 LEDs that Bergie cites, thats still all of 8 watts, or about the same as a full power night light or Christmas tree bulb.

I don't think it's a matter of if the RRs will change to LEDs, but when.

[Puckdropper]

"When" will probably be when the current lights burn out. Replacement LED bulbs at AutoZone are about $15 (when I was looking at them), which I would say would last the typical service life of a car. (~10-15 years)

[Anonymous]

On the Belt Railway of Chicago, most of the signals are now lit with LED's. I can attest they are much brighter and you can see them for miles if at the right angle.

[Anonymous]

As others have said power consumption for LEDs is significantly lower than an ordinary incadescant bulb. I have three of the single lens traffic lights fitted with
LEDs on the end of my boat dock as safety lights for boats. The cost is about $36 per unit vs about $3.50 per long life traffic light bulb. I used the LED inserts. It does get a little cold in the water in winter even in Texas and to change the bulb requires an extension ladder in the lake plus a little swimming. Not a pleasant thought this time of year. The safety lights are manditory on docks at my lake (lake board rule) and I want them for the legal liability issue. There are two types; those with pig tail leads and the screw in type. Both types operate on 120 volts, although 12 or 24 volt types are available. The units are either 8 or 12 inches in diameter, depending upon the size of the housing you have. Bought the housings on eBay for under $20 each. Vendors can be found with the search engines. I bought my LEDs from Lights to Go.

I heard that initially some railroads had misgivings about LED due to the color emitted. The red is very railroadish, however the green is a little lighter than the traditional railway signal. I do not think that any sober engine crew member would mistake the lighter green for anything else than GREEN!

[Hugh Jampton]

LED signals are becoming more common round this way. Also LED marker lights are installed on a number of trains as well.

[miniwyo]

I like the idea of LEDs as a whole, I work backstage as it is my major in college and we are required to have a flashlight but it mist be colored blue as blue does not tavel as far as other colors of light, I use a Mini-Mag light and I have gone to Radio Shack and bought some blue 3v LEDs and used them in my mag, It is so much brighter and i don't go through batteries as fast.

All the stop lights in town are LED now as well, I have noticed that alot of trucking companies around here have started installing them on thier trucks and trailers. LEDs are a great innovation and will not be out dated anytime soon.

[mikeyuhas]

QUOTE: Originally posted by CShaveRR

I think we had a thread a while back about these LED signals, how they don't just fail, but slowly dim until they're useless at some point. Of course, we haven't had the required time to see that on any of the traffic lights yet.

I had a nice chat about LEDs with a product manager for a signal manufacturer a little while ago. He said there are a lot more electronics involved in LED circuits. For instance, every now and again, the signal bulb is automatically tested. In a conventional light bulb signal, it's a trivial matter to send a very low voltage through the bulb to verify it's not burned out (i.e., there would be a little resistance versus an infinite amount if the bulb were blown). The low voltage isn't enough to illuminate the incandescent bulb (it would be a bad thing for a dark signal to come alive every few seconds), but would be sufficient to light up the LED array. I don't recall the scheme they use for testing LEDs, but it's far more complicated.

He also mentioned that the light output from an LED is fairly consistent throughout its lifespan, but they tend to brighten slightly prior to failure.

Perhaps a C&S person here could shed more, ahem, light on this subject.

[CShaveRR]

Thanks, Mike, for the info on LED failure.

I think the problem would be that on a signal light, you'd have a lot of little LEDs. If one fails, it probably won't be noticed. If ten fail, it still isn't worth going in and fixing (if it's noticed). But at some point, you're going to have a signal that's not going to be very bright, and will be missed. I really hope they never allow things to get that bad, since LED signals (traffic lights, grade crossing flashers, and that one dwarf signal I've seen, plus all of those signals on the BRC that I haven't seen yet) are just as good as everyone else makes them out to be, as long as they're functional.

[eastside]

Yes, basically you have to consider LEDs as being solid-state components with all the implications associated with the technology. Since they’re used in clusters, which can be lit independently, the redundancy factor is far superior with LEDs.

One other design consideration might be lightning strikes. I have no idea how often or to what extent RR signals are affected by them. Perhaps someone with experience can tell us how robust the current incandescent signals are.

IMO, if the designers can tweak the spectral characteristics, LEDs will rapidly replace virtually all other lighting. Household lighting will be on battery-operated circuits, unaffected by power failures. Table lamps, for example, will be cordless, controlled by WiFi. All this with greatly reduced power consumption.

[Anonymous]

Mickeyuhas touched on the subject that LEDs are solid state vs incadescant bulbs. I had bought a flasher that was advertised for rail/highway crossings to have my dock lights more irrating (and observed) by boaters. It worked fine until I switched to LED. I had to buy another flasher that was designed for LEDs. These control units are 110 volt PC boards about 2x3 inches and will easily fit into a double plastic outlet box. I like the plastic boxes to prevent potential shorting on the steel box. The nice thing about these boards is that they are constant rate flashers and do not look hokey like the flash buttons you can place under a Edison bulb base. I bought these also from Lights to Go and the cost is about $45. They will work on railroad signals fine as I have one on a position light signal. Sorry for the discussion about boats and docks ona train web site, however, electric is electric and what works in one venue will work in another.

[Anonymous]

Talking about the LED flashlights.

I just bought one of those LED pen flashlights at Radio Shack, and WOW are they ever a great thing to have.

They give off a great supply of light and the LEDs are rated as being good for 100,000 hours.

All works off two small AA batteries.

[Anonymous]

We have installed over 20 railway crossings with leds for short lines in canada
They work great actually have installed a pair of 12 inch ones on my garage attached with a motion sensor so that when i get home they flash for approximately 30 seconds and then go to the motion sensor lighting look kinda neat.

[Overmod]

There are relatively cheap ways to test LED arrays on site to determine how many of the elements are out.

1) If you know the starting current, and the change in characteristic over time (whether the individual LEDs draw more or less current as they age) you can measure when the aggregate current draw falls below some critical level -- and use some kind of alarm or alert.

2) The individual lights in the array are diodes -- meaning they don't conduct much, if any, current in the "reverse" direction. You can measure to see if the array, or individual lines within the array, are conducting in both directions (meaning there is damage to one or more of the LED elements) or are dead in both directions (meaning 'burned out' or physically disconnected, e.g. by corrosion)

Some BMWs have a cycling test program to determine whether filaments in the various bulbs on the car are burned out. I know this 'scans' the filaments one after the other because I have put "bulb-replacement" LED arrays in several positions, and you can visibly see the flash when the small pulse of test current -- which wouldn't even begin to make a filament glow -- runs across them.

With respect to driver boards: A typical incandescent light filament is a resistive load, and can be an inductive load. "Cheap" (being a bit technically snobbish here!) driver boards use the characteristics of the load as part of the circuit or its tuning. Better modern ones isolate the turn on/turn off logic from the actual voltage and current being supplied to the devices, which is a good idea with low-current devices like LEDs.

[Anonymous]

I have been seeing these new signals all over various Septa lines in Philadelphia. They seen to shine brighter than the usual signals. I suspect you will probley see them everywhere in a few years.

[railman]

It's, the "wave of the future!"