# LED Lighting for Passenger Cars



## TiCoyote (Dec 11, 2018)

I have two lighted Bachmann Spectrum passenger cars. The lights aren't very bright, and I want to replace them with LEDs. 

I saw this kit: https://www.randbmanagement.com/modeltrains/orders.htm

For $4.50 plus shipping, that's not bad, but I'm thinking if I buy the components in bulk, it might be cheaper. 

Question 1: Can I buy an LED strip like this: https://www.amazon.com/Flexible-Kitchen-Christmas-Non-waterproof-Daylight/dp/B00HSF65MC

Cut a small section, and wire it to a bridge rectifier and capacitor? 

Question 2: If I try to source a kit like the one listed above, how do I know which LED Driver Chip and which bridge rectifier I need? 

Thank you.


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## DonR (Oct 18, 2012)

Yes. go with the LED roll of strip lights. You'll find
that you can cut them off in sets of 3 LEDs with
a 12 V DC input. If you have DCC you'll need
to precede them with a diode rectifier.

I used 2 of the 3 LED strips in each car.

Get the warm white. The effect coming out of
the car windows is florescent lighting.

You can use the strip lights for buildings and
the like.

Don


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## TiCoyote (Dec 11, 2018)

I forgot to mention. I'm on DC not DCC. 

Which bridge rectifier do I want?


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## traction fan (Oct 5, 2014)

*Any one*



TiCoyote said:


> I forgot to mention. I'm on DC not DCC.
> 
> Which bridge rectifier do I want?


TiCoyote;

The LEDs don't draw much current so many bridge rectifiers would work. The only significant difference in bridge rectifiers is the amount of current they can handle. Since even two of those strips in an HO-scale car will draw less than an amp, any bridge with a 1 amp or higher rating will work.

Have fun;

Traction Fan:smilie_daumenpos:


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## traction fan (Oct 5, 2014)

*Series resistor?*



DonR said:


> Yes. go with the LED roll of strip lights. You'll find
> that you can cut them off in sets of 3 LEDs with
> a 12 V DC input. If you have DCC you'll need
> to precede them with a diode rectifier.
> ...



Don;

The strip lights have a separate power supply that is not included. LEDs need a resistor in series or they will burn out. Does the strip have resistors built-in, or did you have to add a resistor when you wired your passenger car? I'm wondering if the series resistor is in the power supply?

regards;

Traction Fan:smilie_daumenpos:


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## Lemonhawk (Sep 24, 2013)

DC presents more of a challenge. Hopefully GunRunnerJohn can assist. With just DC it might be best to use 3 normal LED's in series rather than the 12v strip of 3 as you can get the LED's to turn on sooner. In any case you'll need a bridge rectifier and some sort of regulator. My choice would be a LED current driver that supplies a constant 20 ma to drive the LED's. This may make the LED's really bright, but a little paint or tape would dim them down. Using a voltage regulator and resistors is another option but would require some trial and error to get them to turn on and to adjust the brightness.


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## Stan D (Feb 1, 2019)

But here's the problem with LEDs and DC power. As soon as you back up your train, you've burned out the LEDs. LEDs are polarity sensitive, unlike a incandescent bulb.

I have a Hornsby passenger train, two A units(one powered), and a passenger car. The A's have headlights, but only the forward moving unit lights. There is a diode (not a *L*ight *E*mitting *D*iode) in the circuit that blocks the electricity from the rear unit. A diode will pass electricity in one direction, so the correct diode should allow LEDs to work in this situation, albeit only in one direction.

And BTW, those strip lights are usually 12 volts, so they would work without any other power supply.


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## gregc (Apr 25, 2015)

TiCoyote said:


> I'm on DC not DCC.


the problem with DC is that the LEDs won't turn on at low throttle settings. Putting them in series which is a good idea with DCC just makes it worse, as well as adding a bridge rectifier which adds another two diode drops (1.4V).

if you would normally have three LEDs, has anyone considered using 6 LEDs, 3 with one polarity and 3 with the opposite polarity, wired in parallel and with a single resistor series?

with them wired in parallel, they should start turning on when the track voltage gets above one LED voltage drop (~ 3V). And with them wired in both polarities, there's no need for a bridge. (the cost of the bridge and extra LEDs may be comparable.

if there's 3 LEDs operating at ~3V and drawing 10ma each from a max track voltage of 12V, a resistor of 300 Ohms ((12 - 3) / 0.03) seems appropriate


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## Stan D (Feb 1, 2019)

gregc said:


> if you would normally have three LEDs, has anyone considered using 6 LEDs, 3 with one polarity and 3 with the opposite polarity, wired in parallel and with a single resistor series?


Unlike a standard diode, LEDs won't handle the current, so with 2 circuits of LEDs, each will burn out upon reversing.


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## gregc (Apr 25, 2015)

Stan D said:


> Unlike a standard diode, LEDs won't handle the current, so with 2 circuits of LEDs, each will burn out upon reversing.


there's a series resistor


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## Stan D (Feb 1, 2019)

A resistor only reduces the voltage, and does nothing to block the reverse polarity or reduce current.


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## gregc (Apr 25, 2015)

an LED is a diode, and because it's a diode it is polarity sensitive. It blocks the current when the voltage is reversed. It will not burn out if the reverse voltage is within limits (~10s V). since it's in parallel with the conducting diode, the reverse voltage will be no more than the forward voltage of a conducting LED. 

have you tried doing this? i have.


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## Stan D (Feb 1, 2019)

An LED is a diode that produces light, but is extremely sensitive to incorrect polarity. It will not hold up to reverse polarity A standard diode is an extremely hefty component made to stop electricity in one direction.


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## gregc (Apr 25, 2015)

have you ever used a two terminal bi-color LED?


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## Stan D (Feb 1, 2019)

Not personally. But they are designed to be bi-polar. A standard LED isn't.

Truthfully, I can't say if those strips the OP mentioned have polarity protection. But it would be an expensive experiment if it didn't.


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## Stan D (Feb 1, 2019)

It just hit me as to what you're talking about. And that would work, except you'd still have a voltage threshold issue. LEDs don't like less than operating voltage. A dimming circuit for LEDs doesn't lower voltage, it "flashes" it at a rate we can't see. A LED dimming circuit is called a Pulse Width Modulation circuit, which gives the appearance of dimming by changing the width of the pulse. For your house, there are both dimmable and not dimmable LEDs. The dimmable ones have the circuitry to convert lower voltage to PWM.


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## Stan D (Feb 1, 2019)

I've thought long and hard about this, as I prefer passenger trains, I like a decently lit car, and I don't run DCC. I may have to step up on the DCC thing.


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## TiCoyote (Dec 11, 2018)

Okay, I think I found a capacitor, LED controller, and bridge rectifier that will all work on Mouser. 

What gauge of wire?


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## gunrunnerjohn (Nov 10, 2010)

Wire size for LED lighting of a model car is non-critical, you can use very small wire. For O-scale passenger car wiring, I use #28 and #30 wire a lot.


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## Stan D (Feb 1, 2019)

What kind of LED controller? And what's the rectifier for? You're already using DC power.


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## gunrunnerjohn (Nov 10, 2010)

Stan D said:


> And what's the rectifier for? You're already using DC power.


If you're running on DC, the polarity reverses, so a bridge rectifier allows you to have lights for either direction.


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## Stan D (Feb 1, 2019)

Didn't know it would do that. I'd still like to know what kind of controller he's looking at. Mouser only has hundreds to choose from.


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## gregc (Apr 25, 2015)

don't you have to reverse the polarity on DC track to reverse the direction of the locomotive?

wouldn't you want the passenger car light to be on when the loco it moving in both directions?

won't you need some way to rectify the voltage from the track to drive an LED lighting the passenger car?


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## Stan D (Feb 1, 2019)

Apparently, a bridge rectifier will keep the polarity the same when the track power is reversed.


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## TiCoyote (Dec 11, 2018)

I found a pretty good article here: 
http://www.trainelectronics.com/LED_Articles_2007/LED_104/index.htm


I'm looking at the CL2N3-G LED driver, the DF005M bridge rectifier, and the ESK108M016AH2AA capacitor. 

Parts range from 30-45 cents each. I figure I'll buy 10 sets and see what I can do with that. 

I'm also thinking about putting some red lights on the sides of a few boxcars.


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## gregc (Apr 25, 2015)

do you understand that the LEDs will only come on when the track voltage is greater than there combined forward voltage if placed in series?


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## wvgca (Jan 21, 2013)

for LEDs in buildings, it doesn't matter if they are series or parallel, as you would be driving them with a seperate power supply ... 

but for LEDs in passenger cars, or cabooses, you would be better off if you ran them in parallel mode , that way the turn on voltage would be less than series mode ... only applicable to straight DC, not DCC as that voltage is higher, and constant ..


in straight DC mode, parallel LEDs should start to come on when your loco starts to move ..


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## TiCoyote (Dec 11, 2018)

Speaking of putting lights on boxcars, I need wheels which are insulated on one side but not on the other. How do I figure out which wheelsets are like this? 


Will either of these work? 

https://www.trainworld.com/manufacturers/athearn/athearn-90506-ho-33-metal-wheelset-short-axle-8/
https://www.trainworld.com/manufact...nn-42904-33-flat-back-wheel-sets-12-per-card/


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## Stan D (Feb 1, 2019)

If the picture is right, those Bachmann ones will.


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## Lemonhawk (Sep 24, 2013)

I've used the CL2 before. It may make the LED's bright but it solves the large change in voltage you'll see from the throttle in DC. You might try driving 2 LED's in Parallel from a single CL2, that would split the 20 ma current to 10ma on each LED which would make them a little dimmer! The CL2's and bridge I have are surface mount. A whole 'nother lesson in soldering to undertake! Just putting a resistor in series with the LED will only raise the voltage at which the LED will turn on as the CL2 is a constant current device and it will still drive 20ma thru the LED essentially ignoring the resistor. Similarly, putting the LED's in series will only cause the LED's to turn on at a high voltage, so stick with 2 wired in parallel with no resistors. By the way, because of the bridge rectifier and the use of the CL2 the lights will work on DCC also! Have fun trying this out and tell us what you come up with!


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## Stan D (Feb 1, 2019)

Wow. I've learned so much in this thread, but am still conflicted. But it does seem that the OP has decided on a path for him, so cool. I may have to try the whole CL2/rectifier/cap thing before I decide on DC or DCC. I'm probably a year from starting a layout (it'll be August-ish before I even get the house!!), so I have time.


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## TiCoyote (Dec 11, 2018)

I bet I can use this copper tape to make pickups for the wheels! 
https://www.amazon.com/Bullet-Face-...s=copper+tape&qid=1550065679&s=gateway&sr=8-5


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## gregc (Apr 25, 2015)

you need something that applied pressure

you can buy something


you can make your own


tried and true use of kadee #5 springs


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## Stan D (Feb 1, 2019)

I was thinking of cutting my own from brass or copper sheets from Michael's. And I say Michael's because we don't have any hobby shops near me.

I have an Athearn passenger car that has the trucks ready for a "kit" to run power in to the cabin.


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## wvgca (Jan 21, 2013)

kadee number five springs have a few advantages ....
they are the right hardness ..
most of the sizing is already done
they are relatively easy to get


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## Eilif (Nov 6, 2017)

That KD box spring method is brilliant. I'm not doing passenger lighting yet but I've got a spotlight flat that needs repair and I've got more than a few messed up KD box springs that for some reason I never threw out.

Thanks!


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## dcyale (Nov 24, 2012)

*DCC and DC anti-flicker constant brightness circuit*

I have been working on a solution for this problem. They make 5 volt LED strips. Using a 5 volt voltage regulator and a bridge rectifier I came up with this circuit:


http://www.dcyale.com/circuit01.jpg

It is a combination of a couple circuits others developed, and I am sure someone else has come up with the same or similar as it is not a complicated solution. 

It should work at anything over 7 volts. 

I am at the point where I am going to etch a couple of circuit boards and see how they work in the real world. It's a one sided board so I'm trying home etching.

The EasyDEA link is: https://easyeda.com/dcyale/5-volt-constant-anti-flicker

Dave Yale
www.dcyale.com


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## gunrunnerjohn (Nov 10, 2010)

I'd suggest a circuit like this. You can leave out the 22uh choke for DCS, otherwise this circuit will do the trick. The bonus here is this is a constant current design and will allow you to easily and precisely vary the current to the LED's. With a voltage regulator, there is only a very narrow band of voltage from very dim to over-current.


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## gregc (Apr 25, 2015)

when driving LEDs, why not use a current regulator https://electronics.stackexchange.c...or-circuit-referred-to-on-the-lm337-datasheet using an LM-317?


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## gunrunnerjohn (Nov 10, 2010)

Greg, that is the LM317T on my design.


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## gregc (Apr 25, 2015)

sorry. i got confused by the mention of a voltage regulator.


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## TiCoyote (Dec 11, 2018)

I've purchased a number of items, and here is some of the cost breakdown per unit: 

1000 mF Capacitor: .15
5mm white LED: .02
LED cut from an LED strip: .04
LED driver chip: .47
1.5 amp bridge rectifier: .57 (though I can find them for as cheap as .12)

I have found that I can connect a portion of the LED strip directly to a DC power source, and the LEDs will light up without blowing out. 

Considering both cost and ease of installation, I think that the cheapest and easiest option is to connect an LED strip to a bridge rectifier, and then run that to pickups. 

The LED strip I got seems to have internal driver chips and/or resistors between every lamp, so I can cut the thing as long or short as I like, and the fact that there's less wiring is always nice. Plus, the strip is adhesive, so I can stick it right to the roof of the car.


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## Stan D (Feb 1, 2019)

Most strips are made for 5 to 24 volts DC.


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## gunrunnerjohn (Nov 10, 2010)

Actually, the vast majority of the LED strips are made for 12VDC, there are some for 5V and some for 24V, but not nearly as many.


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## DonR (Oct 18, 2012)

Ticote

Those LED strip lights are the best and easiest way
to light cars and buildings. As you have noticed,
they are a series of 3 LED sections. You can cut off
each section or perhaps use two still connected. Each section
will work, generally, with a 12 Volt DC input.

Many of us like the 'warm white' version. In passenger
coaches the effect is that of florescent lighting.

Don


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## Stan D (Feb 1, 2019)

gunrunnerjohn said:


> Actually, the vast majority of the LED strips are made for 12VDC, there are some for 5V and some for 24V, but not nearly as many.


If you look at Alibaba, you'll see the 5 to 24 volt rating on most of them. And after all, virtually all of them are made over in that part of the world. They are marketed here in the States as 12 volts for simplification. If they come without a power supply, a 12 volt wall wart is more easily found than others.

I've done a fair amount of LED party lighting and in the early days, Alibaba was way cheaper. Amazon has since caught up.


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## gunrunnerjohn (Nov 10, 2010)

Stan, when I go looking, I find mostly 12V strips. In any case, I've found the 12V to be the most useful for what I do.


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## Stan D (Feb 1, 2019)

No question. All I'm saying is that they'll work with more and less than that.

And that might work out for me. I like lit cars, but I'm still running DC. I just can't commit to DCC. But it hit me that strip LEDs will light at a lower voltage at reasonable track speeds.


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## TiCoyote (Dec 11, 2018)

I bought a 5v strip. I set it up last night. It seems to flash at certain voltages. It works well at a high level, and it works and is dim at a low level, but it flashes or pulsates in the middle. I wonder if an LED driver chip would fix the problem.


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## DonR (Oct 18, 2012)

My guess is that is the nature of LEDs.
They are designed to light at or 
above a certain voltage.

I have a set of 120 V LED floods that were claimed to
be dimmable. However, when dimmed below a
certain level they flicker and flash.

Don


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## dcyale (Nov 24, 2012)

Is there an adjustable buck boost type converter that does a set up and step down to a regulated voltage. It there was a bridge rectifier to adjust polarity and a big capacitor to eliminate flicker in front of it, that would seem to address DC and DCC inputs. 

Of course I mean a cheap, small board. 

Maybe something like this: https://www.aliexpress.com/item/DC-DC-Automatic-Buck-Boost-Power-Module-Step-Up-and-Down-Board-Input-3V-15V-Output/32962900443.html?spm=2114.search0104.3.135.682e7eb9JzQeUP&ws_ab_test=searchweb0_0,searchweb201602_5_10065_10130_10068_10890_10547_319_10546_317_10548_10545_10696_453_10084_454_10083_10618_10307_537_536_10902_10059_10884_10887_321_322_10103,searchweb201603_16,ppcSwitch_0&algo_expid=27cb6a27-2c3c-4d71-a267-77e1d75cbe64-19&algo_pvid=27cb6a27-2c3c-4d71-a267-77e1d75cbe64&transAbTest=ae803_3

This is a set voltage output but cheap. I have never used a buck boost and am not very familiar with them. 

Maybe: https://www.aliexpress.com/item/LM2596S-DC-DC-LM2577S-Step-Up-Down-Boost-Buck-Voltage-Power-Converter-Module-Non-isolated-Constant/32857565021.html?spm=2114.search0104.3.86.682e7eb9JzQeUP&ws_ab_test=searchweb0_0,searchweb201602_5_10065_10130_10068_10890_10547_319_10546_317_10548_10545_10696_453_10084_454_10083_10618_10307_537_536_10902_10059_10884_10887_321_322_10103,searchweb201603_16,ppcSwitch_0&algo_expid=27cb6a27-2c3c-4d71-a267-77e1d75cbe64-12&algo_pvid=27cb6a27-2c3c-4d71-a267-77e1d75cbe64&transAbTest=ae803_3


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## wvgca (Jan 21, 2013)

first one doesn't go high enough, 15v is very marginal for DCC or DC..
second goes into proper ranges, is a little expensive though....
have you thought of a voltage regulator by itself, a lot smaller , and easy to customize?


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## Stan D (Feb 1, 2019)

I think that first one would be fine for DC. It seems to me if you're using DCC, you aren't having the same problems as you do with DC. And it shouldn't be a problem with DC unless you're in the habit of running at full throttle.


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## dcyale (Nov 24, 2012)

The idea is to run a strip of 5 volt LED lights. DCC is easy. I was wondering if there was something to address low voltage at low speed on DC. I think I'll order a few of various types to play with. Of course, from china it'll take 6 weeks for them to get here.


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## Stan D (Feb 1, 2019)

In recent times, Amazon has some good prices.


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## ssgt (Jan 8, 2013)

bridge rectifier with a cap to smooth out the current resistors or pot to regulate voltage?


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## Stan D (Feb 1, 2019)

ssgt said:


> bridge rectifier with a cap to smooth out the current resistors or pot to regulate voltage?


Good link to a article, page 3, post #25 of this thread.


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## TiCoyote (Dec 11, 2018)

Here are some photos of the car with a 5v LED strip. It's really bright, but it works great!


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## gunrunnerjohn (Nov 10, 2010)

That's why I put an intensity control on my LED lighting controller.


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## TiCoyote (Dec 11, 2018)

gunrunnerjohn said:


> That's why I put an intensity control on my LED lighting controller.



What do you use for an intensity control?


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## gunrunnerjohn (Nov 10, 2010)

Here's the diagram of my lighting module. This is a constant current design that is designed for constant voltage command operation.


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## TiCoyote (Dec 11, 2018)

I have a loco (Mantua, 4-6-2, Pennsylvania) that I bought on eBay. It arrived without a bulb or holder for the headlamp. I could have bought an incandescent bulb and holder for around $10 from eBay, but instead, I decided to wire in an LED. Works great! 

I used a "white" LED, and it has a noticeable blue tint. I had ordered 100 white LEDs from eBay for $4.30 from Calif. 

I just signed up for AliExpress, and I ordered 100 "warm white" LEDs for $0.91. I'll probably swap it out when the package arrives. 

I'm getting a little better at soldering. Feeding the wires is still a bit of a hassle.


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## TiCoyote (Dec 11, 2018)

Here are some photos of the wiring and the loco.


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## Stan D (Feb 1, 2019)

I'd say the cool white would be better. At least for headlights. I just downloaded a train theme background for Windows 10 (follow me here), and one of the pics is a front shot of a loco (GP?) at night in snow. The whiteness stands out, and I don't think it's contrast against the snow. So it sorta hit me that the lighting on our models seems too warm. I prefer warm LEDs over cool, but not so much in this case. 

I guess you'll have the choice, as soon as that slow boat gets here. I'll be watching to see what you find.


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