N&W Caboose Lighting -or- When One Thing Leads to Another...

[Fluesheet]

Way back in the day, I completed a N&W CF caboose project (AMB model) that I had decided to put lighting in. Wouldn’t it be cool, I wondered in my outside voice, if I installed a function only DCC decoder so that I could control two individual lights in the caboose, turning them on as the brakeman or conductor boarded the caboose (in my imagination) and lit first one kerosene lamp, then wandered to the other end and lit the other? I certainly thought so!

(you can find the gory details of the complete build here:
<!-- m --><a class="postlink" href="http://www.zealot.com/forum/showthread.php?t=155662">http://www.zealot.com/forum/showthread.php?t=155662</a><!-- m -->)

The end result looked something (well, exactly) like this:



There was one problem (and this is where the good Dr. “Lights? I don’t need lights – they just complicate things” Wayne starts snickering…). FLICKERING! Not every now and then; the “off” side of the flicker was mostly every “now”.

So when I started this,


I figured I’d address the issue. Being just knowledgeable enough about about electronics to cause myself problems, I decided the answer was CAPACITANCE. Something that would keep the lamps a-glowing across whatever issue was causing the flicker. Sound decoders use this to keep the sound alive if a current interruption is encountered. I figured the same idea would work for lights so I built this:



(BTW, I take no credit for the design. This exact circuit was designed by a gentleman on a yahoo DCC mailing list I’m on)

On board this mule is the TCS FL4 function decoder, with a 25 volt 470 microfarad capacitor, a 1/2 watt 100 ohm resistor and 1N4002 diode (the last two in parallel) between the striped negative lead and the blue common wire. The idea being that the capacitor would store a charge that could be dumped to the circuit when it went dead, with the diode controlling which way the current went, and the resistor slowing down the initial charge of the capacitor so that the system didn't see the sudden rush of current as a short. (this gives me a headache every time I think about it, so give me a few moments…). Ok, better. Importantly for later, the trucks were those from the caboose pictured above - I’m a tester – I needed at least one control.

With much anticipation, I put this sucker on the track and was elated to find that the flickering was… Wait… Still there? So I put ANOTHER capacitor in parallel with the first – the flicker was smoother, but the lights still flickered. Doh.

Time for the project to switch from a proof of concept /level of capacitance test for the new twins to trouble shooting a problem that wasn’t what I thought it was. Hmm.

More later!

[OBJack]

Hi Fluesheet,
I am your typical "if it smells like it's burning it's probably wired up wrong" type of electrician, but if I understand you correctly you have a problem with light flicker in a caboose/coach whatever.
Maybe this is what you need.
It is a masterswitch product called "Flickerfree", and I know he mails worldwide.
http://www.dccconcepts.com/masterswitch.htm

Blow.... having just opened the page to give you an address he hasn't got what I was looking for listed yet.
Basically here are a few facts,
1 cm wide
2 cm long
Input AC, DC, DCC, 9 ~20 volts
output suitably powered to direct drive LEDs
easy to Install between pickups on the coach
Storage cap of 200,000 microfarads (whatever they are)
He sells packages of 1, 3, or 6 lots of "Flicker Frees" which include all the Leds, resistors( for a duller white light) and instructions per pack.
So a 6 pack includes: 6 flicker frees
30 x G/White LEDs
2 x red LEDs
10 x 1000 ohm / 1K resistors & instructions
I do have his catalogue and it is listed there so an e-mail to Richard would be a good bet.
He is very knowledgeable and is only to happy to give any info required for free.

Jack

[upnick]

Hi Guys,


Here is a link to the flicker free light set from DCC concepts ........

<!-- m --><a class="postlink" href="http://www.modelrailforum.com/forums/index.php?showtopic=4556">http://www.modelrailforum.com/forums/in ... topic=4556</a><!-- m -->

Installed in coaches here but it can be adapted of course Richard Johnson at DCC concepts can supply some pick up springs for the lights as well he has just marketed try a mail here for information.

Ph +61 8 9437 2470 or <!-- e --><a href="mailtoales@dccconcepts.com">sales@dccconcepts.com</a><!-- e -->

[Fluesheet]

Maybe this is what you need.
It is a masterswitch product called "Flickerfree", and I know he mails worldwide.
Storage cap of 200,000 microfarads (whatever they are)
Jack

Thanks OBJack and upnick...

That sounds like a fine device, and I would definitely take a look at it - once I use up the 5 years supply of capacitors I bought (they're cheap, and cheaper yet if you order in quantities - a false economy considering I only need two!)

200,000 microfarads is ALOT - an article linked off upnick's link states that in the author's case, the lights will stay on for 2-3 minutes when removed from the rail (consider that I have a whopping 470 microfarads for comparison!)

Matt

[Fluesheet]

Troubleshooting
After finding that the capacitor mule still flickered as badly as before, it became apparent that I had a mechanical contact issue. One of the three contact points was suspect:
- wheel-rail
- axle-wiper
- wiper-kingpin screw
Tightening the kingpin screw snuggly against the wiper solved most of the problem, but created one obvious issue: the trucks couldn’t turn
and one less obvious issue: the trucks were slightly out of square, so only three of four wheels was making good contact with the rail (note the slight gap on the left most wheel).



Research
The situation reminded me of an article I read, I think in Model Railroader, sometime in the past 10 years on improving wipers.

The gist of it was this:
- buy brass tubing with .1” inside diameter
- Cut the tube slightly shorter than the axle on your wheelset (assumes metal axles )
- File the tubes in half so they ride on the axle
- Solder the tubes for an axle set to a phosphor bronze strip and drill and kingpin hole in it.
The idea is to increase the contact surface area. Sorry, no pictures. I started down this path, until finding the resolution in the next section.

Another interesting resource I stumbled across was the page at this link (interesting site, by the way), which gave me ideas for later…

<!-- m --><a class="postlink" href="http://www.1905railroadmodeling.com/tender_wipers/">http://www.1905railroadmodeling.com/tender_wipers/</a><!-- m -->

Resolution
I solved both the kingpin and the wheel contact issue by making the wiper into a spring where the kingpin screw passes through (I used my Kadee trip pin adjustment pliers). This allowed two benefits:
- It gave the truck a suspension of sorts – the trucks can now pitch and roll. Wheels stay on rail for good tracking and electrical contact.
- Constant contact between the kingpin screw and wiper, even in the above conditions. More contact improvement.



98% Success!
I mounted the trucks with the modified wipers on my original caboose and found solid lights! No capacitors, no resistors, just a better engineered pickup system!

The caboose with this configuration would still flicker it’s lights across some frogs. Not bad, but then I remembered that 1905 site listed above, and my project got ready to take off on it’s third tangent.

More later,

Matt

[Russ Bellinis]

Too late to help you, but for others, a wiper from an MDC tender would work without the need for fabrication.

[Fluesheet]

Thanks Russ. Are the MDC wipers axle wipers, or do they wipe the back of the wheel?

I'm happy with the axle wipers I have - once I figured out how to get good contact with the screw.

Matt

[Fluesheet]

2% Solution
While I was on this project, I wanted to solve the other 2 % flickering, which would require all wheel power pickup. At this point, the caboose is picking up one pole from two wheels on one truck, and the other with the two wheels on the other truck. To pickup power from the insulated side of each wheelset, I’d need to devise a wiper for the backside of the insulated wheel.

This would lead to obviously better lighting across dead spots such as frogs, but also better reliability over time as wheels and track conditions changed. Stumbling across the 1905 link in my previous post had already given me the idea to use Kadee centering springs, and it’s a good one.

Backside Wheel Wipers
This photo shows the three steps to create the additional wipers for the backside of the insulated wheels. From right to left:
- Stock Kadee #5 centering spring
- “Arms” bent and base of spring shortened
- Base drilled for a 1-72 screw (I may use an 0-80 next time).




Wiper with wire lead soldered on, drilled and tapped truck bolster, and shortened 1-72 screw (it had to be shortened to prevent contact with the wiper on the opposite side)




Fitting to the Caboose
The big problem was how to get the power from the wipers on one side to the kingpin on the other without having a mess of wires. Unfortunately, my caboose is sealed, so after weighing some options such as installing metal brake piping and rods/levers to carry current, I landed on the much simpler solution pictured below.

I glued .015” phosphor bronze wire alongside the center sill. One end of one wire is connected to wiper pictured above, the other end is soldered to a washer through which the kingpin screw passes on the opposite truck. This way, power picked up on either end enters the carbody in one place. No internal rewiring needed.





100% Success!
This last photo is mainly to display how the bent axle wiper looks installed. That arch in the middle was the key. The result is 100% flicker-free operation – and it did give me some ideas about how to do it better the next two times…..



The weird thing about this adventure? Not only am I still intending to light the cabooses under construction, and not only will they have the additional pickups described here, but I plan on adding the originally planned capacitors as well. I've got some of the work done, and it's a good learning opportunity for me.

Finally signing off,
Matt

[Steamtrains]

WoW....I had the same problem with a caboose (see avatar pic) which I proudly foresaw as bringing up the rear of my consists, lights blazing and proclaiming its presence to everyone....No such a thing happened.... That bugger would flicker so much it'd give me a headache....So I disconnected the lights.....

Sometime (in the near/far future) I'll reconsider this issue. I'll probably stick a battery in there and turn it ON/OFF with a magnetic reed switch.

You're to be commended for showing tremendous tenacity and resourcefulness in licking this problem....

[Russ Bellinis]

Thanks Russ. Are the MDC wipers axle wipers, or do they wipe the back of the wheel?

I'm happy with the axle wipers I have - once I figured out how to get good contact with the screw.

Matt

The MDC wipers are axle wipers. To get power from both rails to the lights you would reverse one truck and run the wire from the front truck to one lead on the lights and from the other truck to the opposite lead. You might be able to get the same thing from Bowser as long as steam engine kits have continued availability. I'm not sure who else besides brass manufacturers make steam engines with the locomotive picking up power from one side and the tender picking up the power from the other side. With all of the repowering kits Northwest Shortline makes for steam engines, they probably also offer ready made brass wipers.

[ocalicreek]

My 'Maggie' has got an 'N' cell battery clip and spst switch for the Utah Pacific marker lights bringing up the rear. Maggie is an MDC Open Platform combine, length reduced and cupola added to become a Drover's Caboose. The battery and switch are in the baggage section. The sliding door windows in that area use an old stage set trick, with window glass installed and painted black from behind. Reflects well but conceals the interior.

Lemme see if I've got a picture of her all lit up...probably in a few weeks what with all the packing, etc. Thanks for sharing your trials and tribulations. Here's hoping for even more success as the project progresses.

Galen

[doctorwayne]

Nice to see that you stuck with it, Matt, until you solved the problem.
For anyone needing axle wipers, Bachmann offers their Spectrum tender axle wipers as separate parts (Part No. H114X-MT032). These are made to fit the tender trucks of their locos, but could be modified to suit other situations, or, you could order the shouldered mounting screws to go with them (Part No. 10310) and the accompanying brass washers (Part No. H114X-MT054) . The wipers appear to be formed from phosphor bronze sheet, about .005" thick, and have good springiness.

Wayne

[Fluesheet]

Russ and Wayne - Thanks for the information on additional sources of axle wipers. When I first went looking for some a year or two ago, I was surprised how hard they were to find. It seems I saw them everywhere until I needed them.

Mine are stainless steel from Richmond Controls (<!-- m --><a class="postlink" href="http://www.richmondcontrols.com/">http://www.richmondcontrols.com/</a><!-- m -->). I'm pleased with them - the have a lot of surface contact with the axle which I would think would help with reliability down the road. They are very difficult to solder, however - phosphor bronze is easily the better choice if soldering is involved.

Galen - I'd like to see your drover caboose; I'm having a little trouble picturing your lighting implementation. Pics are needed! Battery power seems to be an excellent idea, if planned for. I'm too heavily invested in my over-engineered solution to change my ways! (setting the decoder to strobe / firebox flicker / mars light or some other effect occasionally for sh1ts and giggles makes it all worth while though...)

Steamtrains - If you decide to take another swing at your caboose lighting, ping me. I'd be glad to give you a hand! Watching a lit caboose meander around your layout in a darkened room can be a lot of fun.

Matt

[doctorwayne]

Watching a lit caboose meander around your layout in a darkened room can be a lot of fun.

Matt

Matt, that was part of my rationale for removing the lights from all of my trains - watching me meander around a darkened layout room would probably prove entertaining, too.

Wayne

[ocalicreek]

watching me meander around a darkened layout room would probably prove entertaining, too.

...especially if you're, ah, 'lit'.

Just packed 'Maggie' today, in fact, she's sitting in the back of my truck, all ready to make the trip to the new place tomorrow, along with the layout and a truckload of train magazines, kits, etc. The reduced weight from the magazines will lower our shipping costs, plus I just don't trust movers to handle the trains. Nice too, to think the trains will be the first things into our new home!

Pictures when I can find them. Until then I'll just enjoy yours! Great work!

Galen