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After years of scheming and dreaming about making my own trains, I finally decided to break down and buy myself a 3D printer. I selected the Qidi XPLUS, a light industrial model that I have some familiarity with from work.


I wanted to make a model of a locomotive that wasn't easy to find in O Scale. I had just returned from a trip to the Trolley Museum of New York in Kingston and had taken detailed photos of an uncommon engine in operation. The museum's World War II surplus Whitcomb 65-tonner has been restored to (mostly) working order with a handsome new paint scheme. I found that although there are some nice HO Whitcomb models, I couldn't find any for 3-rail O Scale. Challenge accepted!

Number 9 at the Trolley Museum of New York

I had a K-Line S2 diesel chassis with truck-integrated motors that had been given to me by a TCA friend. I tuned up the motors, took measurements from the frame and started making Solidworks drawings that I could slice and print. I made some truck buffers and a new fuel tank for the frame.

whitcomb buffers first print

After a few evenings of effort, the cab files were done and ready to run. Each cab takes about 36 hours to print plus a few hours each for the smaller parts. So far I've used ABS plastic for everything since it's strong, a little flexible and easy to sand or paint.

first prototype under print

Getting the right printer settings for a complex part is an iterative process. The first print failed due to poor bridge settings while the second used excessive support material that was hard to clean off. I used the damaged cab to make fit checks and settle the railings and other frame details. I painted and added Microscale decals to the frames and trucks while the prints were running.

test fit with misprinted shell

On the third try I had a cab that printed to my satisfaction. Here's the finished locomotive, the Whitcomb 65-Tonner Number 9!

number 9 takes to the rails 1

number 9 takes to the rails 2

I managed to fit in an ERR Cruise Commander board in as well as LED headlights and illuminated number boards. Maybe I could have wedged in a sound system, but I already had an extra sound car to pair it with. With extra cab weights and well-lubricated gears, it runs smoothly and even manages the 5% grade on my layout with a couple of cars!

The printer files are mostly settled and I still have quite a bit of filament left, so I've been keeping the Qidi cranking over the past few days and nights. I've already produced a duplicate kit and am partway through another. I've got some ideas for one or two more Whitcombs for myself, but I might run off some extra kits to sell or trade if I find anyone who is interested.

third body set

So what would you, my fellow Forumites, like to see next? Comment below and include some pictures for ideas!

*edit to fix photos


Images (8)
  • Qidi XPLUS
  • whitcomb buffers first print
  • first prototype under print
  • test fit with misprinted shell
  • number 9 takes to the rails 1
  • number 9 takes to the rails 2
  • third body set
  • Number 9 at the Trolley Museum of New York
Last edited by Trainguy Ken
Original Post

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That print looks good, the roof looks especially great - I see no layering! I've been toying with the idea of getting a 3D printer to print my own O scale items as well. I've assumed I would need to get a resin printer if I wanted models with the level of detail I'm looking for, but I think your model here is a great example that traditional filament printers can produce great models.

@0-Gauge CJ posted:

That print looks good, the roof looks especially great - I see no layering! I've been toying with the idea of getting a 3D printer to print my own O scale items as well. I've assumed I would need to get a resin printer if I wanted models with the level of detail I'm looking for, but I think your model here is a great example that traditional filament printers can produce great models.

I thought the same about resin and filament, CJ, until I realized just how small you can make the print layers with filament. ABS filament can be temperamental but with a good printer and the right settings, it makes strong, functional prints with just a little bit of texture to them (which as you can see can be sanded or painted for a finer finish). I've tried resin printers before but I felt the prints were too fragile and kind of a pain to clean up.

@John A posted:

Great project! Thanks for sharing! JohnA

@DMASSO posted:

Excellent rendition.

@BenLMaggi posted:

Nice job!

@Gerhardt posted:

Very cool.  I see a lot of neat possibilities for our hobby with this technology.  

Thanks for the kind words guys, I really appreciate it. I've got plenty more projects in the works so stay tuned for future updates!

That looks like a McKeen car body could be ginned out!  Something l would buy!

Aha, McKeen cars! I've been interested in those for a couple of years. Might have some news on that front by the weekend, but here's a teaser for now... Stay tuned for updates!

McKeen trailer first prototype is on the bed!

@Eddie Marra posted:

Fantastic job!  One of the railroads I go to a few times a year, Wanamaker, Kempton and Southern, has one that's from the last railroad it worked on, the Lehigh and New England.  Always loved the look of this switcher!

That's a good tip Eddie, I'll have to look for that scenic railroad the next time I go to Pennsylvania.


Images (1)
  • McKeen trailer first prototype is on the bed!

Here's a neat one for my fellow Forumites on the West Coast. I made a McKeen car mail trailer!

mckeen trailer interior lighting

The trucks are postwar power trucks that I took apart and cleaned up while the frame is a hand-cut piece of sheet brass. The car body and doors, of course, are 3D printed in ABS. It took almost 48 hours of straight printing to do all five parts! The body is a scale 31' or about 7.75" long on the tabletop.

mckeen trailer doors slide open

The doors do slide open and closed! I put in a little rectifier with some dimly-lit yellow LEDs to represent the oil lamps in the mail sorting compartment, the effect is pretty neat. I'm thinking about designing an interior for the next one that I build since the doors reveal quite a bit of the car's insides, which presently aren't much to look at.

mckeen trailer on the shelf

This will have to hang out on the shelves in my train room until I can build a McKeen motor car to pull it. That's in the works and will take me some time to finish drafting. In the meantime I've already made some improvements to the printer files for this trailer so I will hopefully be able to print it this weekend.

I found the McKeen Motor Car Company Historical Society's website to be extremely useful as a reference. They even have some of the design drawings that show car dimensions and interiors. Check out some real McKeen trailers at this link!


Images (3)
  • mckeen trailer interior lighting
  • mckeen trailer doors slide open
  • mckeen trailer on the shelf

My O Gauge Whitcomb 65-Tonner is now a 2 of a kind model. You've seen the modern Number 9, now it's time to meet the WW2 era Number 7!

The build process started with one of a few haggard MPC era Lionel locomotives that I picked up at the NETCA meet in Hudson, MA a few weeks ago. These had the same kind of motor trucks that the K-Line S2s had so I thought they would be easy to convert. I ended up having to modify my 3D printed buffers and run off some new couplers to make them work.

custom trucks

Turns out that the MPC frame was 2" longer than the K-Line S2. I ended up cutting the material out of the middle with my Dremel tool. The end railings had to be moved in and the exterior ones had to go to make all of the cuts. Eventually I was left with a jigsaw puzzle that didn't really fit together. Hmm, how to make 4 pieces back into one?

cutting down the frame

JB Weld to the rescue! I'd never used the stuff before so it took some experimentation to figure out. I ended up repurposing some of the parts I cut off the body to brace the sections and then applying the epoxy in two layers to smooth it all over.

jb weld to the rescue

Creating the locomotive body was comparatively easy. I printed duplicate copies of the last set, cleaned them, painted them Rustoleum Moss Green and added some Microscale military decals. I ended up going for a greener variant of this scheme that I found online. The decals were still a little wet when I clear-coated them in Rustoleum Matte Enamel, which interestingly worked better than the Micro-Sol at sinking them into the shell.

number 7 painted and decaled [2)

After some tedious wiring, I managed to cram the original cab weight, an ERR Cruise Commander board and a full set of headlight and number board LEDs into the engine. I crimped up some paperclip handrails and it was time to check my work!

number 7 is finished [2)number 7 is finished [1)

After a little fiddling with the harnesses, all the LEDs were in the right spots and the Number 7 was ready to defend my layout! She runs smoother and has brighter numberboards than the Number 9, which is rewarding considering how much extra work I had to do in modifying the frame and trucks.

While I was making this I stumbled across some photos of armored Whitcombs from the war. Anybody like to see me tool up one of those? I'm always looking for new project ideas so leave a comment if you've got any!


Images (6)
  • cutting down the frame
  • jb weld to the rescue
  • custom trucks
  • number 7 painted and decaled (2)
  • number 7 is finished (1)
  • number 7 is finished (2)

As I've been talking about my 3D printing adventures with my friends, I've been hearing lots of great ideas for new projects. My good friend Kris showed me his collection of Borden milk cars and told me about his interest in making some of his own to decorate for his family's own dairy farm.

I started by studying images of the original Borden milk cars and making a 3D drawing of the carbody. I used this common 8" long MPC era flatcar that I've had in my parts box forever as a guide for sizing.

designing the milk car

I made some printer files, broke open a fresh roll of white ABS filament and cranked out a herd of car bodies. No milk will be  left to go sour on Kris' railroad!

getting ready to ship

At the end of the print job I still had a bit of filament left, so I made one final body for myself. After a bit of filing and sanding I twisted up some handrail stanchions and fabricated railings to fit the mounting holes I had designed into the shell. I decided not to paint it since it was already white, but if I ever do another one, I'd like to try a dark green livery. A thick spray paint like Rustoleum tends to smooth the surface a bit better than just sanding and clear-coating.

handrails and brake wheel

In the meantime, I started working on that old MPC frame. I started by painting it light blue (to match the real car in the Illinois Railway Museum) and drilling some mounting holes to match the ones designed into the body. Slivers of a car body that dramatically failed during printing were repurposed as drill guides. I had to bore out the mounting posts on the carbody too-- ABS tends to shrink during printing so holes often end up undersized. I used about a 0.1" drill bit on the body and a 1/8" bit on the frame to fit #4 wood screws.

drilling holes

While I was waiting for the glue to dry on the body and frame, I started digging around for some trucks. I noticed in my research that the original Borden milk cars had special high-speed trucks that didn't look much like the typical freight trucks I had in my parts bin. I didn't want to pilfer trucks from my handsome Lionel reefer cars so quite naturally I drew up and printed my own!


Here's a comparison of the result. From left to right:

1, a classic Lionel postwar staple end freight truck. Rugged and reliable, if a little ho-hum.

2, Ken's Kustom Trukk with home printed coupler and truck frame. It uses the same wheels and axles as the postwar truck. As shown above it is a 3-piece assembly with frame, coupler pocket and coupler printed separately.

3, a fine Lionel scale milk car. This is one of the older cars that has the nice working couplers, not one of the newer releases which we have all probably read about on this fine Forum.

postwar my and modern milk car trucks

The trucks seemed to work pretty well after a bit of sanding and shimming. They fit the car frame perfectly too. The car seemed a little too light so I added some scrap metal under the body to help keep the wheels on the rails.

adding weights

After putting on a few homemade decals and some Rustoleum Matte Clear, the milk car was ready to roll!

new haven milk car done

Now of course, the key question on everyone's minds: will those home-made trucks and couplers hold up to mainline service? I put together a milk train behind one of my favorite Railking steamers and ran it through the S curve on my layout at full speed to find out!

I really enjoy inventing all of these trains, it's a lot of fun! Some of my friends in the parts business have commissioned me to print some reproduction parts for them. I'll put some pictures up for the OGR crowd when I get them done!

*edit to correct a typo


Images (8)
  • designing the milk car
  • getting ready to ship
  • drilling holes
  • postwar my and modern milk car trucks
  • IMG_20211006_180132566
  • handrails and brake wheel
  • new haven milk car done
  • adding weights
Last edited by Trainguy Ken

@coach joe and @BillYo414: Thank you for the kind words, I appreciate your compliments. I am having a lot of fun figuring all of this out, even though it's not always smooth sailing (this next project in particular took three whole weekends of trial and error). I hope to continue to entertain you and the rest of the Forum!

My good friend and fellow TCA member Joe Fanara has commissioned me to design and print some rare Marx parts that, although often found broken, have never been reproduced. He loaned me a couple of rare original parts and I immediately set to work making digital copies!

The first part was a Marx 2-stage rocket that came in most of the Cape Canaveral sets from the 1950s and 1960s. Joe did have an intact original that I was able to get dimensions from. I drew the first stage section first, figuring out how to draw the obtuse angles in the fins. It took some time but I got the angles and curves right.

2 stage rocket first stage screencap from Fusion 360

The second stage was comparatively easier-- it's mostly just a bunch of cones stacked up and a couple of fins all at nice right angles.

2 stage rocket second stage screencap from Fusion 360

After a sequence of dramatic failures figuring out a new color-- red ABS prints hotter and with poor plate adhesion for reasons beyond my understanding!-- I managed to produce a 9-hour print profile that reliably produced 2 sets of rockets on an easy-to-remove raft.

marx 2 stage missiles fresh off the plate

The result was very satisfying-- a close match to the original! Just a little sanding required to sharpen up the fine edges.

Original missile [white) versus Ken's reproductions

Now for the really tricky part: making the special bracket for the Marx flatcar that carried the rockets. Joe did not have a sufficiently intact bracket to lend me, although he did have a civilian version of the flatcar that was made from the same mold. I found some auction records online and, by taking careful measurements of the carbody and comparing auction photos, I was able to generate a 3D drawing.

rocket flatcar bracket in Fusion 360

The gray ABS filament was fairly agreeable, although printing this odd bracket with many small features and no nice flat sides was a considerable challenge. I ended up developing a profile that used heavy supports that allowed the brackets to be printed laying flat without ruining all of the detail on the lower side. This made cleaning the parts difficult, but I was able to figure out a way to remove the supports without damaging the brackets.

brackets in process [2)

The moment of truth: assembling the car! I was very happy to find that the rockets fit perfectly on the brackets. A unique cargo to spruce up a humdrum freight car!

The Marx Cape Canaveral Rocket Carrier Car comes together!

I showed Joe the first prints last weekend and he was very excited. He asked me if I could print a few more so he could display them at his table at York (the biggest model train show in the world!) and see how many of his fellow Marx collectors need some for their own military trains. Six days to turn out two dozen parts... Challenge accepted! I already had a head start on the brackets since I had kept the gray reel on the printer.

Marx rocket brackets freshly de-supported

I finished off the gray brackets and switched back to running rocket parts with the temperamental red filament. After several days of nonstop runs I had assembled a small forest of missiles.

Forest of Marx 2-Stage Missiles

I finished the last parts early this morning and delivered them to Joe this afternoon. Mission accomplished! Hopefully lots of Marx military collectors will be very happy with my handiwork next week.

Hope that everyone has a nice weekend! I've got quite a few more repro parts to draw up and fabricate.


Images (9)
  • marx 2 stage missiles fresh off the plate
  • 2 stage rocket first stage screencap from Fusion 360
  • 2 stage rocket second stage screencap from Fusion 360
  • Original missile (white) versus Ken's reproductions
  • Forest of Marx 2-Stage Missiles
  • rocket flatcar bracket in Fusion 360
  • brackets in process (2)
  • Marx rocket brackets freshly de-supported
  • The Marx Cape Canaveral Rocket Carrier Car comes together!

I have just finished a particularly complex 3D printing project: reproducing a Marx rocket launcher! Here is the original Marx car from my friend Joe Fanara's collection next to my painstaking recreation. The missile is a modern reproduction that I believe is made from the original molds (these repros are abundantly available although the launchers themselves are not).

Original Marx vs Kens Kustom Launcher

The launcher consists of 3 plastic parts that snap tightly together. The cowl piece on top also contains a long spring that fires the rocket. You can see that one of the rocket supporting brackets on the vintage car is broken-- a very, VERY common area of damage on these cars. I understand that these launchers came in several colors including red, which is convenient since I still have a bit of the red filament left to make them with.

3 Piece Launcher Parts Comparison

I'm sure the first question on everyone's mind is this: does the 3D printed launcher actually work? I pulled out part of my collection of vintage Marx 54mm soldiers to set up an appropriate firing test. A good shooting toy should be able to knock down a platoon of army men!

Marx 3 Piece Launcher Ready to Fire

With a little assistance from my brother I was able to record the momentous occasion for your enjoyment!

I have one more Marx part that I am printing right now, I will post some photos for the Forum if they come out alright.


Images (3)
  • 3 Piece Launcher Parts Comparison
  • Original Marx vs Kens Kustom Launcher
  • Marx 3 Piece Launcher Ready to Fire

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