One of the first special purpose cars the average modeler runs into is the boom car, used with every wrecking derrick. Boom cars are interesting, since they are usually the result of prototype "kit-bashing" to produce a car with a low open end to accommodate the derrick boom plus some sort of storage house for tools and equipment. The Santa Fe has a variety of boom cars but most of them share two characteristics: (1) they are cut down from a passenger car with six wheel trucks, and (2), the "tool shed" is in the center making them 'double ended' cars, capable of coupling to the derrick at either end. Thus, they are distinctive compared to the more common single ended car with the tool house at one end of the car.
Some Santa Fe boom cars were produced by stripping a passenger car to the frame and erecting a corrugated metal shed in the center and angle braced 'gondola sides' for the ends. For my model I chose a car whose sides were cut off waist high and leaving a part of the original body section and roof for the tool house. The original inspiration for my model was the Belen Boom Car, ATSF 191595, shown on page 76 of Santa Fe Diesels and Cars (Wayner Publications). As I worked on the model, I obtained the Charles Trippani photo included here of a second Belen Boom Car, ATSF 194595. This car might be a rebuild of the other but differences in clerestory vents and side doors indicate it is a different car entirely. ATSF 191595 was rebuilt from Baggage Express car 1775 in 1963. My model is free-lanced, using an AHM No. 6262 Santa Fe combine (actually a rider coach). I used the AHM car because it has the channel side sill characteristic of ATSF heavyweight cars. The belt rail makes it different from the Belen car but the overall effect is Santa Fe - all the way.
The body follows car 191595 most closely with some details from 194595. There is one problem with the AHM car: it is a 83' car, while 191595 is a 70' car. I cut my car down and moved the trucks in quite easily but if this seems too much hassle one could leave it long. In that case I'd suggest making the tool house five feet longer to preserve the proportion. I used common materials: sheet styrene in several thicknesses, brass wire, grabirons, scribed wood, Ajax brake gear and wheels, a Cal-Scale UC brake set (AB300), Kadee wheel sets, and MKD-8 couplers, and a few other scrap box items. Common hand tools were used, although a Dremel Tool and Speed Control were useful. I used ACC (cyanoacrylate) cement in addition to plastic cement. Plastic cement is inferred unless otherwise noted.
To begin construction, remove the trucks and set them aside. Remove the roof by releasing the tabs under the floor. Remove the paint from the body. I use Scalecoat remover with great success, but brake fluid will work. There is no need to strip the roof. Wash and dry the body, then replace the roof. Now, scribe the body cuts according to Figure 1; make sure the cuts are square across the roof so that both sides line up. Now, remove the roof and cut it short. Remove the tabs on the center section. Cut off all the knobs on the car body floor.
It is easier to modify the underframe before cutting down the body. Cut off all battery boxes, tanks, and brake gear between the frame cross members. A Dremel Tool helps, but you must cut the speed to prevent melting of the plastic. Remove the four cross-members and smooth off the floor between them. To shorten the car, we must cut down the center frame. Scribe the beams as shown in Figure 2, then cut them down and file smooth. To stiffen the car so that it does not develop a sway back after the door ways are cut, a metal spine should be added to the frame. Remove all detail be tween the two frame members, from bolster to bolster. Brass stock 1/16" x 1 /4" is convenient for the spine, although it must be narrowed a little to fit beteen the center frame members. Cut a piece 46 scale feet long and file to fit. Drill and tap 0-80, 1/4" from each end. Now, lay the spine between the frames, centered between the bolsters, and mark the hole positions on the car. Remove the spine and drill two clearance holes. Attach the spine with two 0-80 screws from the top. Deck planking will have to be cut out around these screws, but a bit of litter will cover them up nicely.
Returning to the underbody detail, cut two pieces of .020" styrene 30 x 3 1/2 scale feet and cement them under the floor to cover the holes in the floor (see Figure 5). Cut four cross-members from .030" styrene (see Figure 2), and install them ten feet each side of the car center. Note that they are not located at the point the center frame tapers.
Now is the time to cut down the body. The belt rail makes a neat edge for the end sections, so cut just above it, and smooth down to it. Cut the doorways flush with the inner floor. Save the car ends for now. Be sure the roof section matches the tool house sides.
In shortening the car, we need to move the trucks inward 17/32", as shown in Figure 3. Smooth off the bolsters, removing around the truck pin. Fill between the frames from the bolster to the new spine with scrap styrene. Cut new bolsters from .030" styrene. 1 1/8" x 9/16" and cement in place. I added new cross-beams at the new truck center made of Plastruct I-beam. Drill 7/64" holes for the truck pins.
Now, get the car ends and cut off the end sills as shown in Figure 4. Smooth them off and remove the grabiron. Attach to the car so that the bottom matches the frame extensions. A prominent detail of ex-passenger maintenance-of-way cars is the three holes in the end sill exposed when the buffer plates are removed. I cut short pieces of 1/16" square brass tube, filed slots under the end sills, and cemented them in place, flush with the bottom of the sill.
Everyone has their own ideas about trucks and couplers, so I will cover my solution here; if you differ you can skip this paragraph and rejoin in the next. To begin, I replace AHM wheels with Kadee 36" wheel sets. This is necessary on Code 70 rail. Secondly, I use body mounted Kadee MKD-8 couplers successfully on 28" radius curves and homemade (irregular) switches. Finally, I find AHM car bodies sit too high on their trucks. Bearing these items in mind, we can proceed. Remove the wheels and couplers from the trucks. Cut off the coupler hanger. On top of the truck frame, file the ridge around the truck pin hole nearly flush. Replace the pin, install Kadee wheels. Reinstall the trucks and check to see that they just clear the body sills when turning. You may need a bit of shimming. To install MKD-8's, file the rivets off the frame members at each end and be sure those brass tubes are flush with the sill. Cut two mounting pads (1/2" x 3/8") from .040" styrene and cement to the under frame. (See Figure 3.) Drill and tap 2-56 for the mounting screw and attach the couplers. Then check the coupler height with a Kadee gauge and adjust if necessary. At this point a test run is indicated. Put some weight on the car to simulate final weight. My critical test seems to be to run the long car next to a short tender and try a sharp crossover. If it runs OK, we can proceed.
This is a good time to install the brake gear. I used a Cal-Scale UC brake set (AB300), placed as shown in Figure 6. The train line is .035" brass wire, the other piping is .015" and .020" wire, following the Cal-Scale data sheet.
Turning to the upper body, cut the car ends from .020" styrene, and fit between the sides. I believe in heavier cars, so I added two ounces of lead in the center before cementing the roof in place. (My car weighs 6 1/2 ounces). The open car floor is 1/32" scribed sheet wood, with 1/32" spacing. The wood extends under the tool house ends. Fill the doorways with a strip wood sill, sanded even with the floor. Make two cleats of heavy styrene to fit across the floor and stiffen the bottom of the house ends. (See figure 6.) These are cemented to the floor, even with the house sides. Cut tool house ends, as shown in Figure 6, from .020" styrene. The upper part should be cut oversize, and filled smooth after installation. Tool house doors are .010" styrene, 6'-3" by 3'-3", centered on the ends. The door stop and track are 1/64" square wire, attached with ACC. The door handle is a flat U of .015" wire. To simulate the rollers, I drilled no. 76 holes just above the track, and put in escutcheon pins, so that the heads just rest on the track. Then I fastened tiny rectangles of .010" styrene over the pins, extending down onto the doors.
We need to trim the doorways, cut into the original baggage doors as shown in Figure 7, right end. With a sharp knife, carefully remove the remains of the hand rails, and shave down the thick portion of the door at the bottom. Now cut a patch of .010" styrene to fill in the baggage door, cement in place, and fill the cracks with plastic putty. To finish the belt rail, cut a strip of .010" styrene, and emboss rivets on it. I still like the old clock gear on a stick method. Attach the rivet strips. To dress up the end corners, make four angels, with rivets, as shown in Figure 7. I used shim brass because I can make neat bends, but .010" styrene will serve. Make the angles to match the belt rail, cut to length, and apply to each corner. Next install grab irons on handrails as shown in Figure 7. I used Northeastern grabs, and .015" music wire handrails, so I drilled all holes no. 78. I could not find anything like the brake wheel gearbox in the Wayner photo, so I used two Ajax gearboxes, glued to a 3/16" by 7/32" pad of .020" styrene. They are attached to the car so that the top projects 1/16" above the car end. Kentron has a brake wheel (X241 ) which looks close to the prototype. These were attached wih escutcheon pins. The scrap box yielded a smokejack which was installed per Figure 7. The only clue to the type needed was the crosswise cap peeking over the roof in the Wayner photo.
The steps at the corners and doorways are typically Santa Fe, a little tricky to form, but worth the effort. I made both from 1/32" by 1/64" flat brass wire. First the side steps: these were probably left over from the baggage car, as they are of two lengths to match the original doors as shown in Figure 7. The steps are shaped per Figure 8. They hang 21 scale inches below the side sill. There is a 90 degree twist at the top, then a right angle under the sill, and a vertical leg fitting in side the sill. A vertical brace is soldered at the center, then bent slightly inward to fit inside the sill. The three top tabs are attached inside the sill with ACC. I reinforced them with a piece of Plastruct angle cemented to the floor.
The corner steps are formed as shown in Figure 8 with a rung soldered in place. The 1/16" bends at the top were rough until I found a pair of needle-nose pliers by Dixon with ultra thin tips. I drilled the inner end and side sill with a No. 76 in order to attach the step with an escutcheon pin. The other end was fastened with ACC.
The final assembly is the "possum belly," located below the floor on the side opposite the brake cylinder. The bottom and ends are cut from .020" styrene. To stiffen the floor, cement a 1/16" Plastruct angle along the inner edge, and five 3/64" Tees across the floor behind the upright dividers (see Figure 9). Leave 3/64" at the outer ends of each Tee to clear the uprights. Cement the ends in place, then the floor, with the angle against the frame. Cut five uprights from 3/64" Tee, and set in place. Finally, add a 1/32" strip of .010" styrene to the outer edge of the floor.
Make five hooks of .015" wire and attach above the "possum belly" for cables. Finally, I added a pair of wire hooks on each side to carry a pair of Details West rerailing frogs. The car is now ready to paint. First, wash it carefully in warm, soapy water (use a regular dishwashing detergent), rinse thoroughly, and dry. Cover the wooden floor. I sprayed my model with Floquil paints though Scalecoat and others work as well. The first step was to spray a coat of Floquil Barrier; next, the underframe was sprayed with Grimy Black. Finally, the car was sprayed with Old Silver, mixed with about 20% Hi-Gloss. At the same time I sprayed an old pair of freight trucks, wheels and all, to be carried at each end of the car.
After the paint had dried several days, I applied Micro-Scale decals from Set 87-79, ATSF M-W equipment. I followed the Wayner photo of 191595. The ATSF herald is located at the center of the tool house with "Belen Derrick Boom Car" below it just above the sill. ATSF 191595 goes at the left end above the sill, with LT WT 111,000 and AQ 7-63 below it on the side sill. Finally, L-70'0" and WK goes on the right end. above the sill. After washing the decals, I sprayed the whole car with Floquil Flat Finish. The last touch was to stain the wooden floor with Campbell Tie Stain.
Loading the car was a challenge to my scrap box. I cemented scale 6 x 6 timbers inside each end to support old freight trucks. The rerailing frogs were painted orange and hung on each side. For the open ends, I rounded up Scale Structures screw jacks and hammers, pulleys left from an Alexander Stiff Leg Derrick, some Kemtron hooks and chain, and a couple of 55-gallon drums. I also added a few ties, and some rusty couplers, air hoses and brake cylinders, and a few tools from a set intended for model tanks.
Some present day boom cars carry heavy blocks for derrick outriggers hung below the sides over each truck. These are about 3' x 15" x 8" and they are painted bright yellow-orange. I cut a few of these from strip wood, painted them, and loaded them in the "possum belly," along with chain and cables. The cable hung on the side was made from ship model rigging thread. After the photos were taken, I discovered that I could hang the chock blocks beside the trucks without interference, so I put Northeastern eye pins in eight chock blocks and hung four on each side on .015" wire hooks inserted in No. 76 holes drilled upward into the side sills. The blocks hang over the center and end axle of each truck.
This completes the Boom Car and your derrick can now travel in style. Even if you don't have room for a complete wreck train, a derrick and boom car with a couple of silver box cars for tools parked near the roundhouse will show your division is ready for trouble.