Project: Fast Acting Circuit Breaker

Today's model trains are more sophisticated then ever, relying on complex computer circuit boards and lots of easily damaged LEDs and other components. The old reliable Lionel postwar transformers had internal circuit breakers but they were only good to protect the equipment from that era. They won't protect today's trains, and it is very likely that a short circuit from a derailment would fry your internal circuit boards before the transformer's breaker would trip. Replacing burnt out electronic boards is expensive when they are available surplus, and impossible when they are out of stock. A simple in-line external circuit protector system is cheap peace of mind. So, I built one as a fun project.

I found plans on the OGR's Youtube channel for a fast-acting circuit breaker box. This is an upload of an older video that I believe originally was filmed about 15-20 years ago. As designed, it had four sets of banana jack binding posts on each side for the input and output wires (a Lionel ZW has four sets of outputs) and it all just barely fit.  

When I priced everything through the video's updated recommended parts sources, the banana jack plugs alone were $90! Since I don't even use that style of connector, I asked on the OGR forum if they were required and found out that they weren't. So, I switched to using inexpensive terminal strips and saved a lot of money. 

The parts I used were: 

(1) fast acting circuit breakers (W28-XQIA-10) that I sourced from Ebay. The numbers in the circuit breaker part number designation actually represent something... the last "10" means 10 amps", and not being an electrical wizard I decided not to deviate from what they called for here. They were $3 each.  

(2) heavy duty terminal strips from Ebay for about $8 total.

(3) a project box. The plans called for a box that today costs $25 and it was only barely large enough to fit everything in it. In fact, you had to solder it all up and then bend the wires out of the way. I looked on Amazon and found a substitute box that is a roomy 8"x5"x3" with external mounting tabs for about $10. Larger, cheaper, and more convenient. Sold!

(4) Red and black 16g wire. I bought a five foot long piece of red/black speaker wire on Ebay for $6.

(5) 14/16g wire terminals. I bought a box of 20 for less than $4.

I started with a scrap of plywood I found in my garage that I cut to size and sanded smooth. I could have left it natural but I decided to paint it black. The project box was marked by placing blue tape on the sides and then laying out the four 1/4" clearance holes for the wires on each side. Because the box is so large, I had a lot of flexibility in where to locate things. I probably could have located them lower down on the sides. I found the drill bits constantly grabbed the plastic box, and the only solution was to very slowly drill down through the side walls. Then, I spun a hobby blade around the holes to remove the burrs.

The project box was screwed to the wood. Then, I attached the terminal blocks to the sides near the holes I had drilled.

The top of the box needed four holes to mount the breakers, and each hole had to be about 5/8" diameter. My largest drill bit was 1/2", but I did have a spade bit that was 11/16" which helped. I should have been smart and bought the correct size bit, or a tapered reamer, but I did neither. I mostly used my metal burr bit to make the holes. As a result, one of my holes was slightly too large and the breaker rotated in it slightly once installed. To prevent this, I glued small strips of styrene around each breaker just to prevent movement. I later painted them black.

The five feet of wire allowed for each of the four channels to be 15" long, which was just about perfect. Honestly, though, another couple of inches of red wire would have made things easier later on. There is plenty of space in the box to cram the extra wires.

Wiring it up was pretty simple. The black wires had some spade terminals crimped on their ends and then they were screwed to the corresponding terminals on each side of the box. For the red wires, I clamped the lid onto the side of my workbench to hold it in place and then soldered on the eight wires. After that, I used some heat-shrink tubing for security. It wouldn't short if the two red wires touched, but they would just jumper over the circuit breaker and defeat its purpose.

Right before I screwed it all up, I took a picture for posterity. 

Well, upon screwing it together I discovered the circuit breakers wanted to pop up out of the lid. My holes I drilled were a little too loose to retain them, and there was so much extra wire down below that it acted like a spring to push them up. I pushed them down and screwed down the lid, but if I were to do it again I might install them on the front of the box as its depth is longer than its height. Or maybe just buy a proper reamer for the holes. 

I haven't tested it yet, as my layout is still in the benchwork stage. But, it was a fun project to work on in the meantime. 

Benchwork: building the table tops / modules

The benchwork is coming along nicely.

The two table tops, or modules as Model Railroad Benchwork calls them, went together pretty easy. To save money (10%) I didn't have them drill any of the through-wiring holes in the cross braces. Since I had a 3/4" forstner bit on hand my wife helped me work the drill press and I cut the holes two pieces at a time.

Then, I glued and screwed the cross braces onto one side of each module. I also added 1" square pieces of dowel stock to the joints as I had done on the legs. Clamps were used to keep everything straight. It went pretty quick.

I let the wood glue set about an hour or so and then removed the clamps and moved on to the next set of joints. In less than an evening I had one side done. 

Getting the other side on was a bit more tricky as I wanted to drill down instead of up. That meant I had to lay the loose board on the floor and then flip the already-completed assembly on top of it. I glued and screwed one joint at a time moving down the line. A second set of hands to help stabilize it while I worked would have been nice, but I managed.

While that was going on I stared at my completed legs and realized the pocket screw holes were bothering me. They didn't look nice. So, I filled them in with some construction adhesive (the screws were stuck anyway) and when that dried I gave the joints two more coats of black paint.

The tops of the legs are milled away so that they slide perfectly inside the module's sides, and the weight of the module rests on the lip in the leg. I had to drill four holes for the wood screws which mount from the inside through the legs into the sides, and I used a template to assist me. The legs were not glued on, as if/when I move to another house I want to take this layout with me. The modules are only 3'x6' and can go out through our basement doors, but not with the legs attached. 

The holes in the legs were drilled and countersunk, and then the legs were screwed on. I wish the kit had used Robertson screws here, but I had to use a Phillips driver and whatever screws they supplied were easily stripped even though I slowly powered them in. When I mentioned this to the company they told me that the screws were the "combination" type and both types of screwdrivers could work on them. Doh! At least they are going to amend their instructions in the future to mention this.

Finally, they modules were flipped over and rolled to their location in the basement. They didn't line up height wise, which was a bit concerning. Then I rolled them some more and they did, proving that my basement's floor is off by 1/4" in places. I was very happy how easy they were to push around though. The overall height so far is 43", which I am happy with. Also, despite being 36" deep I can still reach the back areas of the benchwork though I doubt I will really need to.

I am not sure if I want to permanently bolt them together or just use clamps (like they do for Ntrak modules and such). But, to give the wood more surface area for the clamps or bolts to compress I glued on some 2" squares of thin 1/4" plywood that I bought from Amazon. You can get something similar at a craft store. It is cheap insurance to prevent cracking the plywood from over clamping. 

I clamped the two sections together and drilled a pair of 5/16" holes through the now four layers of wood. Then, a pair of bolts were installed. Now I am ready for the benchwork table tops.

Article Published - MOW Yard Office

My second article for O Gauge Railroading magazine was published in Run 338, the October/November 2024 issue. It describes how to construct a Maintenance of Way (MOW) storage and yard office from a surplus boxcar. I was heavily inspired by George Dutka and mentioned as much in my article.

It was a fun project to work on before I had a layout, and it really let me explore how much detailing could be done in O scale (my previous layouts were N and HO scale). Plus, I used a TTOS club car for the Empire and Eastern and I felt like I was paying homage to the local train club that has helped me over the past couple of years as I build up my O scale knowledge.

This is not my first published article in OGR magazine. Run 333 had an article about removable loads for Delaware & Hudson blue glass hoppers made with real glass beads. This was a natural progression after having done some for HO scale previously.

Benchwork: starting with the legs

I received the benchwork months ago but have patiently been waiting for my week off to start on it. But during my lunch break on Friday I cut part of the box open to find the instructions. I wanted to make sure I had everything I needed on hand and it looked like I did.

Everything came nicely bundled and wrapped to save space and prevent movement, as the wood is easily broken if the shipping company were to drop it. In fact, this is one reason why Model Railroad Benchwork doesn't regularly offer 6' long boards anymore. I spotted the legs (they have a portion milled away at the top, and then four boards with double green marks on the ends that had to be the leg cross braces. That meant the remaining boards were the module's cross braces.

The kit comes with all the hardware which includes special screws designed for Kreg pocket hole assembly. The instructions caution not to substitute regular drywall screws. It even came with a #2 square head long driving bit for my cordless screw driver, which was handy as I don't have any square head Robertson screw drivers.

I followed the directions and glued one cross brace to each leg, and the mounting locations were conveniently drawn in already.  Everything is made from nominally 3/4" thick plywood, and it looks like there are 13 plies/layers used. You can't get that stuff at Home Depot. They align vertically on the legs and four screws inserted into the pockets held the cross brace on, though I used some wood glue for extra measure. The only downside is that the glue caused the parts to slide a little bit so I had to be careful to keep them properly aligned and slowly secure the screws. After an hour, I glued the other leg on. While it is possible that the legs are slightly out of parallel with each other right now, once they are attached to the actual tabletop they will be fine.

While moving them around the joints started to scare me a bit. There isn't much holding the assemblies together and a good bump from my leg could possibly crack the joint, plus they will be on casters so the legs will be jiggling around. For protection, I added some reinforcing pieces cut from 1" square wood dowel stock. No screws were used, just wood glue and clamps.

To secure the casters to the bottoms of the plywood legs, I cut pieces of quality 2x4 lumber into blocks. Using a paper template, I marked the caster mounting holes and transfered the locations to the blocks. The holes were then predrilled.  

I glued on the blocks to the legs with wood glue and secured the joint with a large clamp. No screws or other mechanical devices were used to attach the blocks, and since I only have one large clamp the process too a while to do all eight leg. But, this will give me much more support to attach 2" rubber casters that I purchased at the store.

I took the legs outside and sanded them to remove any rough edges. This was important because unlike regular 1x4 wood, the plywood splinters easily along the sharp edges that resulting from being ripped with the table saw.

Then, I painted everything with black paint. I have never painted benchwork but it is an old theater trick to make them disappear more. I more am hoping it will make the layout appear to be "floating" above the floor. I went to the paint store and was shocked to discover that there are dozens of shades of red and green, probably a hundred variations of white, and only two black colors. I picked "Tricorn Black" (HGSW6258) and got it in satin finish because I didn't want a dull, flat color. A little shine will be nice. I used a roller to obtain a nice stippled finish on the plywood.

The last step was to screw on the casters. Ironically, at this time I discovered the mounting plates did not have all of the screw holes punched out in the same place. It wasn't a big deal to correct though by drilling new holes in the legs.

The next step is assembling the table modules themselves.