CP Executive train in Albany

CP Executive train in Albany

Friday, September 21, 2018

Scratchbuilding a Caboose - Part 1 (building the frame)

This past spring, the local division (Hudson Berkshire) of the NMRA inquired in their newsletter about whether there was any interest in modelers getting together somewhat regularly to work on their NMRA Master Model Railroader certifications. I am actively working on two certificates now but could always use advice and encouragement. The group was to be led by MMR Robert "Bob" Hamm, who was (and maybe still is) the NMRA's National Model Contest chairman. Not only was he willing to give us inside advice and sage wisdom on building models, but he was willing to work with us as we came across problems in our own models. How could I turn down an offer like that?

I didn't want to work on the "Structures" certificate, because I didn't want to build buildings that would just sit around with nowhere to put them. Many of the structures on my layout will be scratchbuilt, but I am not to the place yet where I know their exact dimensions. So, I am focusing on Master Builder - Cars. Eight cars must be super detailed, and at least four of them must be scratchbuilt. Four of them must also earn at least 87.5 points during AP Merit Judging. So, not an easy task. But an obtainable one.

While everyone else in the group is working on structures, I picked a caboose to be my first scratchbuilt car. I probably should have picked a flat car, but I didn't. I really, really love DL&W cabooses with their pleasing symmetry, but as a first attempt it would be tough even though this online slide show presentation starting on page 15 breaks it all down. I think I may build one in 1/8 scale someday, but not today. No, I picked a simpler caboose to model.

A bobber caboose! While toyish, they are definitely smaller and have less windows and roof lines to deal with. Wanting to pick a prototype one to model, I didn't have to look farther than the D&H's own famous #10 caboose. This was the caboose where the first meeting of the Brotherhood of Railroad Trainmen was held in 1883, and it was preserved and is still in Neahwa Park in Oneonta, NY. More importantly, though, was that plans for it were published in the October 1965 issue of Model Railroader.

It had some interesting features which I thought would make it fun to build. First, it used cast journals which look nothing like anything else so I would have to build them (read: extra points if done well). Also, it had no cupola so I could avoid the dreaded seams between pieces which can cost you points during judging. And, it is in great preserved condition so I could weather it lightly.  It even has a seat on the top for a very brave brakeman to ride. I know I wouldn't!

I copied the prints multiple times and used some stripwood (actually, HO scale ties) to build a fixture to lay out the underframe. I had never built a car like this before so I used what I was familiar with, styrene. Some pieces, like the end beams, were made up of multiple laminations of styrene that were then filed to shape. To apply my solvent of choice, MEK, I bought a really snazzy Needle-point applicator bottle from A-West. I picked the 1" tip, size #16 (their smallest) and it still puts out a lot if you squeeze. And, you need to be careful not to bend the tip. But, it works awesome. Why didn't I know about this sooner?

The floor beams were notched for the end beams to fit in, and there was a slight gap under one so I snuck in some 0.010" styrene and trimmed it so that no one will ever know. Well, except the readers of my blog. Oops! The floor is some scribed Evergreen freight car 0.040" thick styrene that I used for the caboose sides. I made sure to have the scribed side face down so it could be seen from below. For the interior floor, I will just put another piece on top facing up. I then took some sandpaper and roughed up the sides of all the boards a little to give it some grain (which I probably should have done before gluing it all together.

The sides are more of the 0.040" thick scribed styrene. I laid out the pieces based on the plans but occasionally I had to stretch the length to get a full board's width in. The windows as well were laid out to fall between the scribed board lines. It was now that I fully realized the value of building this model in O scale instead of HO. I had been concerned that it would be too tiny to handle, and indeed even in O scale it is a small model. HO scale would have been a nightmare to build (in N scale, it would be under 1.5" long)! Plus, working in a different scale allows you to try new things.

The ends were laid out the same way, though for the roof curvature I used the very scientific method of taking the drawing and cutting outside the roof line to make a template which I then traced onto the ends. After that was done, I used a sharp knife and a nibbler to remove the window material and a file to clean up the edges. The board edges also made it easy to see where I needed to remove material. I left the door areas in place temporarily because removing them would leave the ends too fragile to work on and, as it turned out, I didn't now yet how I wanted to handle the doors.

The prototype journals are castings that are pretty distinctive. I looked online at the O scale casting suppliers that I could find (a Walthers catalog would have been helpful) and didn't see anything remotely like it. Nor could I adapt the old Atlas bobber caboose frame to fit. So, I would need to build them from scratch. I took the paper and cut it out and traced the shape onto some styrene. I made 6, three of each side (left/right) and would later pick out the four best. To get the right contour, I had to use three pieces of 0.080" styrene for the first layout, which I then topped with some thin 0.020 to hide the seams. This was filed down to shape, with a portion extending above the journal to represent the area that would bolt onto the truck sideframes.

Next, I some 0.015" thick x 0.040" wide styrene to make the raised edges around the through the castings. Each piece was cut, glued, allowed to dry, and then trimmed. For the curved edge, I tried bending the styrene slowly and gluing it little by little but it buckled. I then applied the curve in three shorter pieces but it still required filling between the pieces with putty. Bob Hamm suggested I use some 0.040" square stock (which I had on hand) to do the curve and because it was thicker it didn't buckle. Once cured, I sanded it down to 0.015" thick and it matched the rest perfectly. Then, I flooded the journals with MEK to soften/round the edges and look more like castings.


  1. Hi: I entered the BRT / NMRA contest to model the D&H #10 when I was 14. I won a "Finalist" certificate at the convention in 1966. I built it 1"/ft & still have it. My bucket list includes getting to Oneonta to see the real caboose. Let me know if you like some pics. Kevin