RPM Chicagoland Chicago Great Western 1937 AAR Box Car Part One

Prototype photo ca. early 1948, Charles Wales, William Hopkins Collection

Naperville, or RPM Chicagoland as it is known now, had been in a bit of a funk for several years. Interest had waned and St. Louis and Cocoa Beach had leapfrogged it as the events to attend on the RPM calendar. One of the things that Mike Skibbe and his dedicated band of volunteers revived was the gift for attendees in the form of a set of parts to kitbash a model into an interesting prototype. They offered a B&O M-15K in 2016. They followed it up in 2017 with a Chicago Great Western 1937 AAR box car that incorporated the distinctive Pullman-Standard Carbuilder’s end.

The entire package included almost everything needed for the kitbash. The attractive Centralia Car Shops box contained a Red Caboose (ex-IMWX) square-corner 1937 AAR box car, resin ends, doors, and details, plus decals (there were corresponding packages for N and O scale modelers.) The instructions were included in the printed and bound meet program, including general arrangement and brake arrangement drawings.

It struck me a little sacrilegious to chop up a perfectly good Red Caboose car. The Intermountain (IM) 1937 AAR cars already come with separate ends, making them suitable models to mate with the resin Carbuilder’s ends. However, when I test fitted the ends to the IM car, I found they were a little too narrow, meaning they did not span the entire width of the car end. I made the decision to cut up the IM car to create a flat kit: sides, ends, roof, and floor/underframe (the prototype underframe had a pair of stringers between the body bolsters and end sills while the IM cars have diagonal supports [see drawing from instructions included at the bottom of this post.] I was willing to overlook this difference if the IM car body was used unmodified. However, since I was creating a flat kit, I opted to use a spare resin floor/underframe.)

Halfway through the car body assembly, illustrating the styrene added at the corners

To create a flat kit from the IM car, I made a series of cuts with a razor saw. The precision of the cuts is less important than avoiding any slips that could damage the side detail. I made vertical cuts to the flat “sub-ends” just inside, finishing all the way into the car body. Once both verticals cuts were complete, I could “flex” the sub-end (still attached at the floor.) Using an Xacto knife, I scored the floor-end joint from the inside of the car body, making several strong passes in both directions. Once scored, it was an easy task to snap away the sub-ends. To remove the sides from the floor, I made two razor saw cuts the length of the car, starting from the bottom of the floor (not from inside the car body,) again with the precision of the cuts not being as important as avoiding damage to the car side detail. I cut all the way through (I did not use the score and snap method because the minimal amount of styrene at the door opening tends to be difficult to get to snap away, leaving one with a side that is missing the portion below the door opening… warning delivered to others, I hope!) Once these two cuts were complete, I removed the excess material from the back of the car sides, leaving two clean and flat car sides.

The sides and ends assembled into the basic car body

At this point, I had two sides, two ends, a roof, and a floor/underframe, ready for assembly. The sides have a relatively thin profile; I wanted a little more surface area for the side-to-end joints. I remedied this by adding 0.125" x 0.125" styrene strip to the back of the sides at the corners, flush with the edges of the sides (leaving some room for the floor and roof parts to be added into the car body.) This provided some extra surface area for a stronger as well as more pronounced 90° joint. I carefully assembled the sides and ends into the basic car body, taking care to ensure that everything was aligned properly and square. Since the joints were resin to styrene, I used ACC. I added extra ACC to the interior to secure these joints. Next I added the floor/underframe casting into the car body. Fortunately, it required almost no filing to fit. I tacked it in place in several spots with ACC and then flowed ACC into the joints from the inside of the car body by adding several drops of ACC and tilting the car body to let the ACC run along the joint until all four joints were filled. I checked the fit of the roof, which required a little amount of filing and added it into the car body, but did not glue it in place at that time. I am still contemplating whether to paint the roof separately as it is black. I also added weight attached to the top of the floor.

The crossbearers as described in the text

The underframe ready for detailing

While I had the floor/underframe casting, I had to scrounge for the associated structural details. I removed the portions of the stringers where the crossbearers are located. I added strips of 0.005" styrene eight scale inches in width to simulate the crossbearer top plates. I fabricated the main crossbearers from 0.010" x 0.100" strips trimmed at an angle to represent the slope of the crossbearers. These were framed by HO scale 1x4 strips on edge. I pre-drilled two for the train pipe, as shown in the photo. I added these to the floor followed by crossbearer bottom plates, again represented by strips of 0.005" styrene eight scale inches in width, but tapered to four scale inches wide at the side sill supports. The crossties are resin pieces from the spare parts bin. The train pipe is represented by 0.020" wire (my holes were not located perfectly, so it is not straight, but from the side, that will not be discernible.) At this point, I was ready to move on to the detailing of the car. That will be covered in Part Two...

A slightly different view of the underframe

This underframe drawing, included in the instructions, illustrates the brake arrangement