I recently finished my latest custom design-- an O Scale DRX-6-4-2000, the unique variant of Baldwin's "baby-faced" diesels specially produced for the Central Railroad of New Jersey.
This engine started off as a Williams FM Trainmaster that the previous owner had converted to TMCC with an Electric Railroad upgrade kit. I covered some of the repair work done to the original chassis in a separate topic. The short summary is, check your pickup rollers for rust on the inside!
After dismantling the locomotive and taking meticulous measurements of the FM's frame and drivetrain, I spent a whole weekend working in Fusion 360 to render the locomotive. Here is an article from American Rails with a good writeup on the whole Baldwin DR6 family. I designed the body as two halves, each small enough to fit comfortably on my 3D printer bed, that would snap together with tabs.
After a couple days of nonstop printing, I had matching body sections printed out in sturdy ABS filament. With a little bit of sanding and filing I was able to get a nice tight fit onto the donor frame while reusing the original body screw tabs on each end.
The next step was to design the pilots for the locomotive. As a compromise between scale looks and three-rail functionality, I went with frame-mounted pilots with just enough clearance to slide an Electrocoupler through.
It took a few iterations to get the fit just right, but I was able to reuse the truck-mounted Electrocouplers that I already had from the donor frame.
With the body and the pilots printed and fitted, it was time to paint! After strongly considering the orange-and-blue scheme used on the DR6s in the 1940s, I decided to go with a blue and white livery used by the CNJ on their road diesels in the 1960s. 2 full coats of Rustoleum 2x primer-paint aerosol did the job just right.
I ended up combining two sets of K4 Pacific decals-- a Central RR of New Jersey boxcar kit and a Lehigh and New England ALCO PA kit-- to produce the effect I was looking for.
Applying the pinstripes was tedious but the results were well worth the effort. The thin stripes resemble the green and gold livery the DR6s wore towards the end of their service in the 1950s.
After topcoating with some Rustoleum Matte Clear, taping in windows and gluing in grabirons, my new locomotive was ready to roll!
Here's the DR6 hauling some passenger cars around the layout.