Lighting Overland Alco Century-series Number Boards


The C425 ran on the A&O for the first time on New Years Eve 2018. I need to shoot some photos of her in her new home. She still needs number board decals, and two micro LED ground lights that fit in brass castings below the cab after I gave them O-scale “root canals.” The other 22 LEDs worked great (kinda went overboard there…) The machined aluminum headlights were well received and easier to install than I had expected.

Today on a frigid New Year’s Day I decided to once again tackle the first of four Overland C424s. Along with the C425 they should be primary coal train haulers. Three of them have the “what was Overland thinking?” inaccessible rear headlight, class and number boards as shown earlier in this thread. I learned that grinding away, or even trying to unsolder a thick piece of brass was impractical. So what to do? Drastic times call for drastic measures!

After a little resistance iron work to thin out weak 1980’s era Overland solder joints I was able to tap lightly on a small screw driver to pop off the entire rear of the long hood. While I was at it the roof walk over the radiator shutters popped off along with the bottom stretcher with the screw mounting holes. No surprises there, I’ve re-soldered several of them. Note that I already popped out the rear headlight MV lenses.

The next photo shows the end of the long hood. I used a “Screaming Banshee Hand Mill” (term learned from Jay Barnaby) with an inverted conical dental burr to grind out a first part of the engineer’s side number board and clear out access to the rear headlights.

Since the assembly was now liberated, it was time to drop it in the ultrasonic cleaner in a jar of lacquer thinner. I didn’t know what type of paint was used, but first guessed acrylics. Here we see the cleaner bowl filled with water and a glass jar with the part and thinner inside. This is why one NEVER uses lacquer thinner to clean locomotive wheels

It worked! The paint blistered and required very little work with an old toothbrush.

A bit more cleaning with lacquer thinner and a cotton bud (Q-tip) should make everything uniformly shiny.


Later this week we should have a day in the 60’s instead of sub-zero at night, so then I can work outside and strip paint off of everything else.

This evening I felt like “making chips” so I tore down the chassis and started a platform for mounting the decoder and a small interconnect board. Sometimes a pre-owned locomotive can be surprising inside. I wonder why a previous owner added unsanctioned shim washers to the front truck bolster but not the rear?

Down at the Sherline mill, this is before notching an end piece for the drive shaft. The material is 1" x 0.125 aluminum.

After the cut. Time to invite Mr. Shop Vac over for a visit.

All finished.


Looking good Bob.

That’s weird on the washer only being in one truck. Is the frame out of square? That’s got me baffled.


Quality work as always! Look forward to the video of this one in action. :grinning: Those washers look like plastic - could they have been an (misguided) attempt to stop a short circuit?



That’s a good thought Pete. I had some similar problems with the pick ups in that area. Had to end up rebuilding the pickup holders because the screws for the trucks attached in that area too.


Kinda wondered that myself. Or perhaps part of the truck was scraping on something under the frame. Those shim washers should have messed up the coupler height. Before I disassemble the trucks to strip the old paint, I’ll put them on my poor version of a surface plate and see if they are the same height.

I’m still pondering the assembly sequence for rear lighting. It is likely that more brass will need to be removed to allow installation of number board lighting from the inside, and packing the interior volume with black modeling clay to stop light leaks. If at all possible I want to also light the outside white and inside red class lights. So this model would sport 24 LEDs as does the C425.


Gray and black never-hardening modeling clay is a fabulous tool for lighting installs. It is opaque and great for both holding things in place and blocking stray light. When packed behind the number boards, it doesn’t have to be pretty since it can’t be seen from the outside.

Here’s the C425 cab before button-up. There is still one more LED to install in the front walkway light that will run along the center “V”.

A new hole in the back of the cab, above the simulated control panels, carries 20 wires into the long hood just below the roof. The red and black wires are very flexible ESU 36 AWG wire. The ultra-fine white and gray wires go to pre-wired 0402 red and white LEDs from LEDBaron, a German eBay seller. Each of those LEDs was dipped in ACC then in setting solution for electrical insulation.


That’s so cool Bob! With those class lights maybe you could use Loksound’s CV settings to make them cycle through off > white > red > off using only one function button. They’ve done this for Bowser and Scale Trains but you can download the files. Hopefully they’ll work in an “L” decoder. Or I’ve seen the sound file schematic for this implemented in a V4 on the Loksound Yahoo list so you could copy it.

Also just in case, I saw your comment about using ACC with the very fine wires. I just did that with 4 SMD LEDs that had magnet wire pre-soldered. I’d mounted them on the back of a number board (stealing yet another of your great ideas!) but the ACC ate the lacquer and all 4 LEDs blew when I switched them on. Luckily the decoder survived!



Pete -

Great idea. Been there, did that, got the T-shirt.

F5 first turns on the number boards, then also turns on white class lights, then switches to red, then all off. It is simple programming but requires a V4 decoder so that it can be added to the sound schedule.

Unfortunately when power is lost (because Darwin causes a short circuit) the decoder doesn’t properly remember which function outputs were on or off. Maybe the V5 decoders will remember.

Sorry to hear about ACC eating insulation on the wires. I’ve never experienced that.


LOL that’s a clever setup - I figured you’d be way ahead of me… :grinning:

I’m hoping the V5 will have better starting and slow revs motor control for coreless motors, as well as the extra functions and improved sound quality. The timing sucks though, right after I finally get my whole roster onto Loksound. I swear I’m so unlucky, if reincarnation turns out to be true, I’ll end up coming back as me! :wink:



Thanks, Pete.:smiley:

Back to decoder installs, I redesigned the C425 connections between what is on the motor/frame and what connects inside the shell. A bunch of 2-pin plugs wasn’t going to cut it for 24 LEDs; connections would be too brittle.

Pondering… what could I do with some 10-pin ribbon cable connectors and some surplus Sparkfun 10-wire ribbon cable? The main plug would be in the middle, with part of the cable heading to the nose and part to the tail. Several wires (including the function common) would need to run both ways.

It worked better than I expected. Here we see a top view of the new decoder wiring connections. Immediately to the right of the decoder is a hand-wired board with 3 green screw terminal connectors. Those connect to the trucks and to the motor. The black blob in the middle is a 1.5KE20CA transient voltage suppression diode wired across the trucks. We can’t put “snubbers” across the rail drops because the A&O is fully-signaled. Anyway, a snubber does almost nothing when tested on the A&O.

To the far right is another board with a 2x5 pin connector. That carries the lighting functions to the ribbon cable.

Here’s the mating connector and the ribbon cable. One of two hand-wired circuit boards can be seen. This one has the resistors needed to drive the LEDs in the nose of the locomotive. The black thing which seems to come out of the bottom of the 10-pin plug is just a cable for the ESU Maxi keep-alive (Power Pack.)

At the rear of the install we see the Tang Band 1925S speaker module and the Power Pack. I need to make the speaker mount more robust; a couple thin strips of double-stick tape are not adequate to hold it in place. A rear PC board that holds the LED resistors is mounted vertically, just to the left of the Power Pack. Both PCBs are mounted with M2 screws into structural supports inside the locomotive. They are not going anywhere.

Note that long ago (early 2000s) we had to hand-tint white LEDs to kill the “blue meanies” and ask Scotty to give them all the power he had. Resistors were sometimes 680 Ohms. With today’s LEDs, the standard 1K is too bright. Fortunately the ESU decoder has dimmer CVs on all outputs, and I’ve dimmed them way down, from 31 (max) to at times 8 or even 4.


Very well executed as always Bob! I really liked your use of ribbon cable. Reminds me I have some Digitrax SE8c ribbon cable and connectors somewhere… Yet another idea I can steal, thank you! :grinning:

Regarding headlight LEDs, I found some so called “12V” 3mm water-clear warm-white which have become my standard as they are a nice colour for modern era, and don’t need resistors which is good news for inherently lazy, ham-fisted types such as I.

But as you say, seriously bright! I’ve got them set to about 10 on the Loksound slider, and I use H/L 2 and R/L 2 mapped to separate functions for dim, set to zero on the Loksound slider. That works well for the ProtoThrottle H/L and R/L switch knobs which go off > dim > bright > ditch light.

That’s interesting about the snubbers. I can’t actually tell what they do for me (I don’t even understand how they work :frowning: ) So I’m going to read your earlier piece about the transient voltage suppression diode again!



Pete -

Thanks for the kind words. I was worried that there wouldn’t be enough vertical clearance for the ribbon connector and cable, but it slid in place like butter. Perhaps that was because Overland mounted some of the motor below deck, leaving more room above.

I’ll order a few of the LEDs you like. Good clear dome 3mm warm-white LEDs are getting pretty scarce. A few months ago I sampled ones from “the usual suspects.” The NCE LEDs had the best color and beam pattern, with only a minor greenish ring or tint in the peripheral beam. So I recently ordered more, and wouldn’t you know, they are now useless “flat top” LEDs. No beam, just flood lights. Ugh!

As for snubbers, the party-line is a 0.1 uF 50 volt ceramic capacitor in series with a 100 ohm 1 watt resistor. When I tried that on the A&O, the resistor got quite warm, but my oscilloscope didn’t show much if any of an improvement in ringing voltage overshoot at about 40’ from a NCE 10A booster, filtered through one of Tony’s DCC circuit breakers jumpered to trip at 8A. Only the TVS (Transient Voltage Suppressor) diodes had any meaningful effect.

YMMV. :grimacing:


Bob. I do have to say that your idea of the TVS was a great one. Cap the voltage, regardless of which phase it is in…great idea! And it doesn’t take a lot of space (well…for o scale. Hehehehe).

I’ve started to use some new connectors that we use at work for “space constrained” connections. Vertical height is low, just need some horizontal space (less than your decoder width).

Part is from Phoenix connectors (PN 1770885). Nice thing about these you just need a PCB to mount or you can flip over and glue to a surface. Wire connection slides inside and can be removed when needed.

I do like your ribbon cable. Makes it so easy to reconnect after done.


Care to share how to tint down the blue meanies?

Please, sir!

  • Mario


Mario -
I haven’t tinted LEDs in years. Today I just buy ones that have the right color temperature to start with. I was a fan of NCE warm white LEDs but the latest pack I ordered came with flat-top LEDs instead of round domes. That makes them useless to me because they are now flood lights.

Some folks have had luck with orange Sharpie pens. Years ago I bought transparent paints at art supply stores, paints intended to simulate stained glass.


I had a good result using Pebeo Vitrail yellow stained glass paint.

I found the yellow too intense out of the bottle so I reduced it with their lightening medium

I found individual jars at Curry’s, didn’t have to buy a whole set.



Pete and Mario-

I couldn’t remember the brand of paint I used for tinting LEDs, but Pete jogged my memory with Pebeo!

For the ca. 2000 blue meanie LEDs I originally tinted (still running in my ABA F3s), using just yellow made them turn green, since yellow is minus blue and those LEDs were greenish-blue. So I added a little bit of magenta, which is minus green. It took some trial and error, but eventually I arrived at an orange paint that worked for that package of LEDs.

When tinting them I made a small LED tester out of a 9V battery, switch, connector, 1K LED resistor, and a 1.5V incandescent lamp inside a white styrene tube (with appropriate lamp resistor in series.) The lamp+tube served as the color appearance reference, allowing me to tweak (not twerk) tints until each LED reasonably matched the bulb.

Over almost 20 years those paints solidified in the bottles.

For the C425 front class lights I lathe turned some small clear polycarbonate lenses, then tinted the outside domes with Marabu Glas procured at a local Jerry’s Artarama. It came in 1/2 ounce bottles. Although it is no longer locally stocked, the sales rep said they can still order it or I could buy it online. I can’t tell from the info on Jerry’s web site, but the “Orange” might be about the right color for bluish LEDs. For the class lights, I used “Dark Green”, “Cherry” and “Sunshine Yellow.” The yellow was too strong and I should have diluted it before painting.

I only illuminated the white and red class lights, using pre-wired 0402 LEDs from German eBay seller LEDBaron. Their red LED is a very pure red color, too pure compared to the prototype. I wonder if a white LED behind the red lens would look more accurate. But the back of the 425 only has only one class light lens on each side, for all colors. A little lever was used to spin a filter wheel between a clear hole, red filter, and green filter. So I needed to put colored LEDs behind each of them. Perhaps tinting the LEDs after insulating them would be sufficient, but I went with red and their warmest-white LEDs.

One can obsess over the color of each LED, or quickly proclaim each LED as “good enough.” That’s an individual call.

All the best.


It is a slowly advancing project but I finally was satisfied with the C424 long hood end modifications, so it was time to solder it back up. I used a PBL resistance iron with a fresh carbon tip, and PBL 50-50 solder paste in a syringe (sadly, no longer available.) The acid flux in the paste worked great, and washed off easily with a toothbrush and warm tap water. The result was a lot more solid end solder joint compared to when it first arrived.

I also went around the cab and long hood re-soldering all of the structural brass members. In my personal experience, many of my O-scale 1980s Overland brass diesels had many brittle, cold solder joints that failed during handling.

The class lights will have to go in first, LEDs then lenses. That will be followed by black modeling clay to block stray light.

Next will be the rear headlights, inserted from the outside, in lathe-turned aluminum reflectors like the C425, the backs of both packed with black clay inserted through the number boards.

Finally the number boards need to go in, again from the outside. The white styrene diffusers need to be smaller in size and the whole assembly held into place by a thin clear number board unit, printed by the Alps in reverse.