Prototype Modeling with Microscale
Soo Line bay window caboose
In 1973, with much of its rib side fleet nearing the end of its useful life, the Milwaukee Road placed an order for 15 bay window cabooses from the International Car Company. These cars were immediately incorporated into the mainline fleet, seeing service from Kentucky to Washington. One of the main spotting features for these cabooses is the roof top thermal generator manufactured by 3M. This rarely modeled piece of technology didn't quite work out as planned and instead of removing the equipment, it was disabled and remained on the roof. These features could still be found on most International (and some thrall and home-built) cabooses at the time of the Soo Line merger in 1985. Using a design based on the Milwaukee prototype, Walthers in its Platinum RTR line, included separate wire grab irons and an accurate paint job, both excellent starts to a prototype model.
Getting started, the coupler trip pins were clipped (including the portion that protrudes out of the top of the coupler), the end rail assemblies removed and the trucks disassembled and set aside. So they don't get misplaced, I returned the wheelset screws into their holes until the model is ready for reassembly. Using prototype photos as a guide, I trimmed Plano Apex-type roof walk material to fit on the roof. As I didn't have drawings or measurements available, the roof rib dimensions were used to determine accurate placement. After tracing lines with a pencil denoting the roof walk placement, I cut five Plano walkway supports from a spare fret, bent them as recommended and laid them out according to prototype placement. After confirming they were correctly lined up, I used them as a template to drill #78 holes and set them with Cyanoacrylate (CA) [MicroBond Thick works well for setting roofwalk components - ed.].
Following a search through hard print and internet resources, I struck out trying to locate accurate drawings of the roof top generator. As I did with the roofwalks, I used dimensions of the roof, roof ribs and walkways to determine rough measurements and translated it to the detail plans. To create the part and maintain the see-through look, I created a floor and sides using Evergreen .040 x .250 strip stock. In order to remain square with the caboose sides, the floor should be angled to match the roof contour and sides cut to match. Once the unit was square to the sides, the styrene was glued using Tenax cement [MicroWeld can be used in place of Tenax for styrene bonds]. After the weld was cured, a file was used to bevel the corners to 45 degree angles and once satisfied with the look of the bevels; pieces of .020 x .040 strip stock were glued in place at the top of the unit to create front rails of the "box". Inside of the box, there appears to be a mechanical unit and an exhaust stack. For the mechanical portion, a small section of .100 x .125 stock was sanded (including the angle to conform to the sides) and glued to the front of the box, facing the propane tank side of the caboose. The exhaust stack was fashioned using two pieces of .040 x .250 strip stock glued together, trimmed to size and sanded to remove glue lines. This piece will fit in between the back rail and mechanical unit, centered between the sides. After assembly, give the part a final sanding using 1000 grit sandpaper to smooth joints and set aside to let the glue cure.
Next up were the plated windows. A common feature on modern cabooses, the plates on this particular caboose were coated with a lighter colored paint and lacked proper priming on the weld seams, allowing rust to bleed through. In order for the model plates to seat correctly on the car, the molded window rivets were removed using an X-ACTO #17 blade, being careful not to nick the surrounding paint. After removal, .005 sheet styrene was cut using a NMSL Duplicutter for uniform sizes and installed, ensuring that the tops of all plates are uniform in height across the car side. After allowing the glue ample time to cure, the plates were masked following the prototype pictures in preparation for the window patches. Several attempts were made to mix a correct color to represent the patches. The blend was finally arrived at by using Polly S paint, ten parts Reefer White, two parts CP Orange. The patches were painted and tape removed immediately to avoid paint peeling off of the factory finished surface. While the paint was out, the bay windows and end numbers were covered with Polly S engine black. Note that when Soo forces were applying the patches on Milwaukee equipment, paint coverage was not always masked off. This is represented by the end patches looking like they were applied by hand.
With the windows out of the way, attention was turned back to the roof. The radio antenna was modeled using .035" Plastruct tubing, cut to a length based on photos. Roof walks were test fit, and installed using Plano's instructions. The area underneath the generator was prepped by shaving ribs down to the primary roof elevation. Using a small amount of CA, the generator was installed keeping the unit squared up with the roofwalks, set back approximately six inches from both sides. A propane supply line was bent and installed between the tank holders and generator. To finish the roof, two sections of .019" brass wire were bent and installed to represent smoke jack stabilizers.
Prior to weathering, coupler cut bars were installed and a beacon with electrical conduit was added on one end of the caboose. The lens housing was made from 1/8" styrenetubing. These parts along with the generator were painted to match the prototype. The end cages were reinstalled and the gap at the top between roof overhang and end panel were filled using CA. Once dry, the areas were lightly filed and cleaned up with 1000 grit sandpaper. The tops were painted Reefer Yellow and the handrails painted antique white.
The weathering and decals were completed in concert with one another. After masking the windows, the sides, ends and roof were layered with chalk suspended in alcohol, avoiding the bay windows. Applying light layers instead of one heavy layer allows the modeler to achieve the streaking seen on the prototype. Once the alcohol is evaporated, a Q-Tip dipped in 71% alcohol allows additional streaking to be introduced. The lube plates and ACI labels were applied after the first layers of weathering were completed. After setting up, additional weathering was added to the decals to meld them into the surrounding areas. Because the Soo lettering was relatively fresh at the time the prototype photos were taken, they were applied over the fresh black paint and finished per Microscale's recommendations. Light weathering was applied to the end decals, nothing was applied to the bays. The trucks were weathered using a color blend recommended by Chuck Derus with additional light and dark rust colored chalks added, the trucks reassembled and installed on the car.
After touching up the weathering to taste, a coating of Tamiya Color TS-80 Flat Clear was applied to seal the weathering and decals.
Using Ready-To-Run models combined with commercially available detail parts and Microscale decals allows today's modeler to accurately represent their favorite prototype with only minimal effort.