Passenger Car Lighting

[jonathan]

Going through the forum history, there are many threads concerning how to light a passenger car.  I've had a car on the back burner that I decided to tinker with a while.  Perhaps this will be helpful.

This in an old Spectrum heavyweight observation car with a non-working light and X2f couplers:



Disassembly is pretty straight forward.  The roof and window glazing is all one piece that is released by a series of tabs on the bottom.  The rest of the parts are held together by small phillips screws.  You can see in the photo I've already drilled some holes in the light "tube" and put in three warm white LEDs:



The LEDs were soldered together, positive to negative (polarity matters).  I added a 680 ohm resistor.  The lights come on at around 6 volts and reached their brightest at around 9 volts.  That should work fine for my DC railroad:





I carefully soldered wire to the pickup tabs inside the car body, in order to easily connect the wiring to the light 'tube':



Now the roof and the body are ready to be connected:



But before we connect, we might as well add a little detail to the car floor.  It's difficult to see inside passenger cars, especially when moving.  So, I wasn't too careful about painting or the passenger figures:







Now put the floor back in and solder the wires together:



The car will only light moving forward (polarity matters to LEDs).  That's OK with a car meant to travel on the end of a train.  It only goes one direction on my railroad.

















Now I need to get the wheels squeaky clean to knock down the flicker and do some exterior detailing and weathering.

Anyway, hope that's helpful to someone who needs to light some cars.

Regards,

Jonathan

[Tom M.]

Jonathan,

Nice work, but there is a somewhat easier way to do it.  Berritt Hill Trains sells pre-wired self adhesive LED lighting strips.  They come with up to 15 LEDs per strip.  These work great in full length passenger cars.  They provide nice even light throughout the length of the car.  You can trim them shorter in groups of 3 LEDs should you have less than full length equipment.   The strips also come with a capacitor built into the circuit.  It holds power for about 3 seconds, which is more than enough time to eliminate the momentary flickering associated with most passenger car lighting.

Tom

[jonathan]

Nice tip, Tom.  Thanks.  I like the capacitor idea.  Will keep this in mind for future projects.

Regards,

Jonathan

[jonathan]

Just finished adding lights to my B&O passenger train.  The good news:  I put two banks of LEDs in each car, wired with opposite polarity.  Now the cars light no matter the direction they are traveling.

The bad news:  I picked up several sizes of capacitors to experiment with.  I burnt out each one of them.  They smoke even better than a decoder.  

I will have to search the internet for tips on wiring capacitors.  Perhaps 16-30 volt capacities are not large enough?  Or that "M.uf"(sp) number needs to be a certain size? If anyone is familiar with these...  Have not heard from Jim Banner in a long time.  Hope you're still around, Jim.

Anyway, when I figure out the capacitor mystery, I'll open the cars back up and install them.  Need to do a better job of hiding the wires in one car, too.  See if you can tell which.

For now, they look nice.  And with a thorough cleaning, they don't flicker that much either.  Enjoy:















One last question:  What happens when I move the train to a DCC layout?  I'm hoping the lights won't come on and no damage will occur.  Perhaps, that's wishful thinking.

Regards,

Jonathan

[Joe Satnik]

Hi, Jon.

Thanks for the nice pics. 

Electrolytic capacitors are polarity sensitive, and explode when the polarity is reversed. 

Two ways to get around it:

Either

1.  Build a diode bridge out of 4 Schottky diodes (1N5817 or 1N5819 on e-bay or NTE 585) so that either track polarity is changed to the proper polarity to feed to the electrolytic capacitor and LEDs. 

(Shottky diodes drop less voltage in the forward direction than regular diodes or regular diode bridges, so passenger LEDs will come on at lower track speeds.)

               l---------->l--------(+DC)-------l<-----------l
(track1)--l                                                                l--(track2)
               l-----------l<--------(-DC)-------->l----------l

Or (but not both)

2. Change to on-board batteries, no capacitors needed, lights stay on while stopped at station.

Three 1.5 volt AA or AAA alkaline batteries in series (=4.5 Volts needed to run LEDs) will last a long time. 

You'll need to mount an underside on-off switch.

Not sure who makes a 3AA or 3AAA holder though. 

I've seen 3 button-battery holders in small devices using LEDs.

You could just use a 4AA or 4AAA holder with all 4 batteries and a higher Ohms value series resistor, or short out the last battery position (+) to (-) to get 3AA.     

Hope this helps.

Sincerely,

Joe Satnik

[Doneldon]

You can also use magnetic switches like those in the "Easy Peasy" lighting products. This is easier
and faster because the cars don't need to be handled to turn lights on and off. Also, some folks
mount magnets near yard throats (on an overhead signal, pedestrian or road bridge, so the lights
turn on when cars leave the yard and off when they return.
                                                                                       -- D

[richg]

Super caps work very well for car lighting. Quite a few people use them.
For polarity, follow instructions.

I have used his ideas. I got this from the MRH website but rather not post the thread here. There was a fairly good discussion with different ideas when using DC and DCC layouts for flicker free car lighting. There are commercial kits sold also.

http://i98.photobucket.com/albums/l267/richg1998/DCC%20lighting/LED_FlickerFree_Circuit_Drawing.jpg

Rich

[jonathan]

Rich, Doneldon and Joe,

Thanks a million for the sound advice.  I discovered the pop and fizzle ('explosion') possibilities of the capacitors.    Now I know to never run current backwards through a capacitor. Wish the camera was ready when one capacitor blew inside the car.  The smoke was scary, but very cool looking as it leaked out from every orifice of the car.

I like the ideas presented for lighting.  I few years ago, you would have been writing 'over my head'.  I prefer the circuitry solution over the batteries, as weight is a concern on my railroad.  If the cars get too heavy, I won't be able to pull around a 6-car passenger train.

I will experiment one car at a time, probably starting with the Combine.

The passenger cars of another brand utilize 12-wheel pick up and don't flicker at all.  So, I'll be able to leave those two as is.  Will let you know how it turns out. 

Regards,

Jonathan