34V DC LED light bulbs for steam locomotives

Bad Order · **Joined:** Sun Jun 23, 2013 1:16 pm **Posts:** 231

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Here is a picture of the current varieties the railroads are using. One on the left is for walkway and number board applicatons. The one on the right is for the step lights and for over the trucks. Left hand bulb puts out light radially to the bulb, right hand bulb puts out light from the end of the bulb only-like a spotlight. Both are bright white light and are labeled "Railheadcorp.com" for the manufacturer.

Forgot to add..they can stand to be exposed to voltage as high as 115 with no damage. They blink on, then go out. They'll come right back on at a lower voltage. Very tough.

I have a feeling they are very expensive, but the railroads are switching everything over to them. I have never came across one that is "burnt out". They are tough and, except for the harsh white light, would seem to be the perfect fit for all your lighting needs. Sounds like some applications call for the dull yellow of the incandescent, and may not look proper with a stark, bright white lamp.

robertmacdowell · **Posted:** Mon Mar 17, 2014 3:10 pm

LEDs come in every color. Yours are freakyblue because your supplier chose that color instead of the traditional warm white you are used to.

Suppliers love to give you freakyblue lights because they're a smidge cheaper. White LEDs work by making blue light and using phosphors to turn that into the other colors*. Yellower light = more phosphors = more phosphor loss... since phosphors will never be 100% efficient.

* Fluorescents do the same thing, but with UV: they make UV and then use phosphors to turn it into visible light. LEDs do not make UV at all. You can also do the same "dial-a-color" thing with fluorescent bulbs, assuming of course that you like to get your lighting from glass tubes filled with mercury.

rggreter · **Posted:** Mon Mar 17, 2014 5:41 pm

When I had these bulbs made, one of the key specifications (for me at least) was to mimic the color temperature of an incandescent bulb as closely as possible. This is a side-by-side comparison of an incandescent bulb (left) and the LED bulb. The LED bulb is both brighter and whiter than the incandescent, but in this case at least some of the "whiteness" is the result of a higher luminous intensity. The bulb illuminated the water glass quite nicely, without the harsh starkness of a typical LED light.

The Railhead bulbs, while fine for number board illumination, would not be ideal for water glasses, gauge lights, etc. These bulbs produce about 270 lumens in the cool side of the color spectrum. They are doubly hard on the eyes with the brightness and the starkness of the light. The bulbs I had made put out around 160 lumens, and while a bit whiter than an incandescent, the light is not at all hard on the eyes. I installed one in one of the water glasses and while noticeably different than an incandescent, it is quite easy to become accustomed to them. If all of the bulbs in the cab had been replaced with these LED you would not have even noticed the difference.

RCD · **Posted:** Mon Mar 17, 2014 8:14 pm

You can get 6,000 lm led lights that run on 35v for under $10. YES THAT IS NOT A TYPO 6,000 LUMENS. They run at 100 Watts.

nevans1133 · **Joined:** Fri Dec 28, 2012 12:17 pm **Posts:** 37

rggreter wrote:

It appears that Nate is a little further ahead of me in the research department, but there's nothing wrong with a little bit of friendly competition is there? I think our goals are the same though - to provide a quality product to the preservation industry and to help keep these marvelous machines going for future generations to enjoy.

I had the opportunity to test the bulbs this past weekend on the PM 1225 with some mixed success. One of the dyno's over-rev'd and the power surge blew out the driver circuit. The LED's themselves weren't damaged, and so with the few spare components I had on hand and a few minutes with the soldering iron we were back in business. The improved circuit performed well and the test bulbs were still burning brightly at the end of the day.

I'll be talking to my manufacturer later in the week to discuss some design changes and to see about having another small batch produced. I'll also have the chance to discuss some of the various requests I've received via PM or the suggestions seen above. In fact, since I do have this opportunity, I'd like to get together a "wish" list of the various types of bulbs that we'd all like to see produced. If you can provide me any information at all (voltage, wattage, base style, size, part number, etc), I'll explore my manufacturers capabilities.

Thanks to everyone who contributed to this conversation.

Rich,

I didn't mean to start a competition. Just wanted to let people know that 32VDC LED's are commercially available. I sell mostly 75VDC bulbs to shortline, regional railroads and mechanics but was approached last year by some in the preservation community who wanted to reduce the load on their dynamo's by installing LED's. Unfortunately I haven't found an LED that can mimic the look of incandescent and that could be improved along with the rough service aspect. I'd be happy to speak with you about feedback that I've received if your interested. Feel free to send me a PM or email me sales@evansgroup.net.

Nate

rggreter · **Posted:** Tue Mar 18, 2014 9:11 pm

Quote:

Rich,

I didn't mean to start a competition. Just wanted to let people know that 32VDC LED's are commercially available...

No worries Nate, I should have emphasized the "friendly" part. There was no offense or ill will intended, but if offense was taken, I most sincerely apologize.

I'll send you a PM when I get a moment. I'd like to hear about your experiences and the feedback you've received.

robertmacdowell · **Posted:** Wed Mar 19, 2014 5:01 pm

LED color should exactly match incandescent color. If it doesn't, you need to order a different part number in LED emitter.
http://www.mouser.com/Optoelectronics/L ... /_/N-8usfj
If the part number does not permit fine enough resolution, then it's time to talk about binning.
http://www.cree.com/~/media/Files/Cree/ ... mixing.pdf

My sweetie said "no freakyblue LEDs in the house". So I ordered 2700k.

6000 lumen LEDs for $10 - true. Remember those halogen torchiere lights that were all in fashion in the 80's, but were banned because they started fires? Brighter than those but only 50-100 watts. However that is just a bare emitter that radiates light at 140 degrees of arc. To have something usable, you need a huge heatsink, correct optics, and a constant current power supply.

The constant current supply is tricky, but you can drive several emitters off the same supply simply by putting them in series. Constant-current supplies are highly resilient, and this too helps your light be adaptable to many input voltages.
http://www.youtube.com/watch?v=uoW5ehXeTEU
(the failures are due to "Made in China", you can source this stuff domestically, go Cree!)
Note also the small emitter shown in the first minute, those can be ordered to specific colors (any specific hue you want) and lensed any way you want, for about $3 an emitter for quality USA units. They are perfect IMO for railroad block signaling, because your former 20 watt incandescent bulb is now a 1 watt LED, and that's a game-changer for going solar.

Pegasuspinto · **Joined:** Fri Mar 26, 2010 11:43 am **Posts:** 783

Over 20 years ago, my Dad had a razor that had a 12-250v AC or DC input capability. I would think a similar power supply could be managed for LED lighting. Maybe even one that could withstand worst case 600 volts from trolley circuits.

One other option on 600vdc systems would be to put a ballast resistor across each bulb. Not efficient or elegant but would get the job done.

robertmacdowell · **Posted:** Sat Mar 22, 2014 12:44 am

Sure, it can be done, it's just a matter of speccing components with sufficient insulation for the highest voltage, and sufficient current paths for the lowest voltage. Though, a single bulb which works on 12-600V may be a bit ambitious :)

If you're going to design a bulb for the 5 bulbs in series application, they will need a little more intelligence so they don't "argue with each other" and form resonances, and so they are non-destructive if mixed with incandescent bulbs.