Hi Dave,
Back again. OK, yes, I found out that my Walthers passenger cars do have metal contacts inside the car for lighting and the power is picked up on the wheels thru the rails. I'm using DCC, so what I was hoping to do is connect a wire to one of those contacts and run that wire to the dome ceiling and connect with 3 LED's on the dome ceiling. I have very small wide angle 3 volt LED's that will work fine. Then run that wire with resistor back to the 2nd contact to make a circuit?? But I'm not sure about this and I don't know if those two contacts are all I need. Do I need to go to the trouble of adding a capacitor? I have several capacitor's that came with Soundtraxx decoders that I have not used, but I don't know their rating. If their rating will work, any chance I could use one of them? I'm still unable to "see" what I need to do even with your circuit diagram. Thanks.
John
Most rediculus problem ever. They may turn the lights on in the station, but otherwise there would only be some foot lighting since people riding in the dome will want to be able to see out.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Thanks for this clarification Dave. I'm sure I will have more questions down the road.
Regards,
JRPNow if I can just understand your circuit drawing I might be able to wire these things.
Hi JRP:
Let me try to translate the circuit into plain English:
The circle represents a rectifier. What that does is it takes the alternating + and - power from the tracks and converts it into DC power where the + and the - are always on the same wires instead of switching back and forth like the DCC power does. The LEDs need a constant + and - to operate. (Well actually they don't but let's not complicate things here.) The capacitor, which is the part with an upside down 'T' with the + symbol over a 'T' with a curved top, acts as a battery but with a very short discharge time. When there is an interruption to the power coming from the tracks the capacitor supplies the missing power but it is only capable of doing that for a few seconds. That doesn't matter because usually the track power will be regained before the capacitor is drained. Once the track power is restored the capacitor will get recharged so it is ready for the next power interruption. The capacitor in the diagram is rated at .1 farads and 5 volts. Some would say that it would be safer to use a 25 volt capacitor but the circuit as shown works and has never blown up.
The rectangular black box at the top of the drawing represents a 1000 ohm 1/4 watt resistor, and the 'V' shaped things are the actual LEDs. Note that LEDs are polarity sensitive. If you hook them up with the + and - reversed they simply will not light but no damage will be done. Just reverse the leads to the LEDs and if the gods are kind they will light up.
I used these circuits in a fleet of cabooses so I added an additional component to the circuit which is a locking reed switch. The reed switch allows me to turn the interior lights off when the caboose is parked. It is not necessary in your situation, and they have become very hard to find so I wouldn't worry about using them.
Here is a picture of the actual circuit. Left click on the picture to blow it up. The capacitor is the round thing with the green rim. The rectifier is the very small black square in the middle (no, the rectifier is not round despite the fact that the symbol for it is round). I'm sure you can identify the resistor. The rest is simply the connections for the wires coming up from the trucks. You can see the reed switch inside the roof of the caboose shell, but like I said, you don't really need that part. The other wires in the shell lead to the marker lights and an LED inside the conductor's office which can be seen through one of the side windows. In your case those wires would lead to the dome lighting:
If you have more questions then don't hesitate to ask!
Cheers!!
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Thank you for these photos and other good information. The reason I want to add lighting to the dome ceilings is to lightly illuminate the passengers inside, both in the UP dome lounge and in the dome diner which has details on the dining tables as well as a waiter holding up a large plate. Becuase I colored the dome "glass" with a transparent emerald green tint I need some lighting to illuminate the figures inside. I'll be using "wide angle" 3v cool white LED's for lighting.
Here's a photo I took in a Northern Pacific Budd dome a few years back:
IMG_0563 by Edmund, on Flickr
You can see continuous lighting on either side of the center air conditioner duct (which uses the inner and outer glass of the center windows as a duct).
Also note the two lights at the bottom of the stair railings. There are recessed lights along the floor and along the steps. Some dome cars had illuminated lucite stair railings if I recall.
IMG_0439 by Edmund, on Flickr
For the most part, the dome ceiling lights were seldom illuminated. The subtle floor lights seemed like they were always on.
I'm trying to locate some photos of a Rapido Budd dome that I have. They do a pretty decent job of lighting the floor (aisleway) below the seats of the dome. This is the most common way you would see the lights on a passing dome car in a train at night.
Good Luck, Ed
The only way I could thing to get power to lights in the top of the dome without being seen would be to use fine wire, like magnet wire, and run one down the front and one down the back, rather than having both sides of the circuit try to run down the same end - just one wire to hide between the frames instead of two. Since the area under the dome isn;t highly visible, runnign a wire from the front to the back to bring the two sides of the circuit together shouldn't be a problem. The wires could be tacked into palce along the window framing using a clear adhesive such as canopy cement or MicroScale Kristal Klear.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Dave, I checked with Walthers and my passenger cars do have wheel pick-up. I was told Walthers Proto cars (prefix 920) and Walthers cars from 2002 (prefix 932) are all capable of picking up power from the rails. I was just not able to tell looking at them. Your also correct....the cars have electrical contacts inside the car that allow for truck power to be sent to an interior lighting kit. Thanks for letting me know. Now if I can just understand your circuit drawing I might be able to wire these things.
Ed, it looks like that walthers kit is for the lower level of the dome car. It does not say if the light reaches the dome interior or not. My domes in question are the Union Pacific "City" series regular domes that were ACF dome design. As I stated, I want to softly light up the interior of the dome since I have tinted the dome "glass" and want folks to be able to see the figures I placed inside. I'm in a modular club and we run trains on a 768 square foot layout.
Fellas, thanks for all the information. I guess I should have told you I wanted lights just so I could light up figures inside the dome glass that I recently tinted with Testors Emerald Green transparency spray (Walthers says they tint the dome windows, but not to my satisfaction nor prototype). In any event that is why I asked about overhead dome lighting. Even if the prototypes did not acutally have overhead lighting that is okay with me. Not trying to be exact on the lighting, but wanted some light inside. I'll check on the availability of a kit and review Mel's expert advice. Note: I too took the City of Los Angeles from Chicago to Los Angeles in 1959 when my family moved from Atlanta to L.A. We did not cross Donnor Summit, however, but instead took the Salt Lake route down thru Las Vegas, across Cajon Pass and into L.A. I remember sitting in the dome at night watching the target signals change from green to red as the head engine passed the signal. What fun!!
hon30critterI thought that Walthers passenger cars already had the power pickup systems installed.
In fact, Walthers has a "dome lighting kit" that may be what you are looking for?
https://www.walthers.com/passenger-car-interior-constant-intensity-led-lighting-kit-fits-walthersproto-acf-budd-dome-cars
I have lots of the older lighting kits with incandescent bulbs that I re-work using LEDs and a "keep-alive" circuit similar to what Dave shows. In other cars I use a similar setup like RR-Mel has expertly done.
Can you get a catalog number for the actual dome car you have? Is it a full-length or "regular" dome?
I thought that Walthers passenger cars already had the power pickup systems installed. In my Walthers Canadian Pacific passenger cars there are power pickups in the trucks and contacts above the trucks where the power is transferred to the shell. Maybe that's not true for all of them.
As for keep alives, here is a home built version that works quite well:
You might want to increase the capacitor voltage to 25 volts or more just to be safe, but this circuit has been used for a long time by Mark R who designed it and nothing has blown up yet! I have a bunch of these circuits in use as well with no problems.
Hi, I'm looking to add low lighting to the interior roof of a Walthers dome car. Any suggestions on how to do this so the wiring does not show? Also, this car runs on DCC so I think I will need some sort of a wheel pickup, a resitor and a capacitor to operate, yes? I have a source for very tiny 3 volt LED's which I think I will be able to string together along the length of the roof of the dome car.
Thanks for reading and any suggestions.
JRP (member of Green River Junction Modular Railroad)