Building AN On30 Class A Climax By Ken Smith Photographs by the author Introduction I wanted a backwoods Class A Climax for use as a MOW engine on my Tall Timber Railroad. I also wanted this loco to look like she was nearing the end of her useful life. Finally, I wanted to be able to build a loco without a huge investment like some of the brass counterparts available in On30. This article will show you how you can convert an Athearn SW 7 into an On30 Class A Climax. This is a very simple conversion that one with basic skills can accomplish. You need only simple tools and glue, nothing else. As a final note I used Minwax Golden Oak stain, as the base color for all the wood. You can use whatever you like, just be sure to pre-stain all wood before gluing together. Touch up all of your cut marks with stain. Preparing The Sw7 Chassis Begin by removing the SW 7 shell from the frame. Once removed you will need to separate the diesel hood from its base. Once this is completed, remove the tapered section of the hood by sawing flush against the stack nearest the side that would be closest to the diesel cab. You will need this section so be sure to hang onto it. A hobby saw can complete the surgery with ease. Trim off the front and rear of the base so that you have a nice squared finish. Finally, remove the light fixture and bracket. You can solder on wires for a headlight if you wish. Be sure to leave yourself plenty of room to string your wires later. This is how the chassis should look Building The Floor Board And Frame. The floor is scale 2X6 wood siding from Mt Albert Scale Lumber. For the floor, cut a piece of scribed siding material 1 ¾” wide by 5 ¾” long. Center the plastic frame onto the backside of the scribed floor. Trace the cutout of the frame onto the backside of the scribed floor. Remove this section with an Exacto knife. When completed, glue the plastic frame onto the floor. On the backside of the floor build a frame with scale 6X6 lumber. I had the frame set back so that the floor hung over the frame by 1/32”. Install NBW castings onto the frame. On the topside of the floor, you will need to add 2 6”X6” scale beams for the boiler support. The beams should measure 1 7/8” in length. You will also need to cut two small wedges from 6”X6” beams that are glued on top of each other. This will be the front smoke box support. Now if you are a bit unsure of this step hold off until you have made the boiler. You can add them after the boiler has been cut to fit over the motor. The completed floor should look like this AND INSTALLED ON THE CHASSIS Making the Boiler. The boiler is made up from a ¾”X1” tee and a ¾” nipple. The tee I purchased from Home Depot had a centerline molded into it from the middle of the 1” side. From that centerline, measure down 5/8” and cut that section off. You can discard that piece. Next, cut a ¾” section from the ¾”nipple and glue this to the ¾” section of the tee. This will form the length of the boiler. Cover the splice connection with a 1/8” wide strip of styrene or in my case, cardstock. Next, cut and remove a bottom section off of the boiler assembly approximately ¾” wide, and the entire length of the boiler. Discard that section. The finished slot should allow clearance of the boiler over the drive mechanism. I used a Dremmel Tool and a cut off disc to remove this section. Sand the bottom of the boiler smooth when you are done cutting. Do not glue the boiler onto the frame just yet! At this point you can add the dome, smokestack, smoke box cover and headlight. I used castings from Precision Scale and Grandt Line. Since many of these castings end up being more to taste, choose the ones that you want on your T-boiler. You will also want to add a top to the T-boiler. I used a piece of scribed wood left over in my scrap box and cut to fit the top with the scribe siding facing toward the inside of the T-boiler. I then sanded the edge for a smooth fit. You could also use styrene to achieve the same result. Finally, glue the small section of the SW 7 body that you removed earlier with the tapered end pointing toward the real of the Climax. You may need to sand or grind some of the plastic away on the inside of the hood to clear the flywheel. When you have assured that there is no interference, glue this to the back of the T-boiler. If you want to add any back head details, valves, gauges, or throttles, this would be the appropriate time to add those detail items onto the boiler. The Water Tank and Stand. The stand for the water tank is made from 2”X6” scribed siding. The overall dimensions are 1 7/8” long, by 1 ¾” wide, by 11/16” high. I used scale 4”X4” on the inside at all of the joints to strengthen the stand. Ad some scribe siding to the front of the stand to hide the opening and match up to the SW 7 hood. Dry fit the boiler and stand onto the floor to check clearance of the motor. Do not glue the assembly together, or onto the frame yet. The water tank is from a 35mm film can. If I had to do it all over again, I would use a black film can, as paint does not like to stick very well to this type of plastic. From the bottom of the can measure up 5/8” and cut through this mark. The bottom of the can has a recycle stamp on it. This stamp can be removed by sanding the bottom. I recommend that you use 400 grit paper and sand in a circular motion. Finally, glue a water tank casting to the center of the tank. Dry fit the tank onto the stand but do not glue it on just yet. Now you can dry fit everything onto the floor. The Cab and Side Frames. The overall cab dimensions are 2 ¼” by 1 ¾” wide by 1 ¾” high. I used scale 6”X6” for the basic frame and 2”X6” for the roof beams. Begin by cutting 4 upright posts 1 5/8” long. Next, cut two roof beams 2 ¼” long. Glue the posts to the bottom of the beams. This makes up the cab sides. Next, you need two beams for the front and rear of the cab. Cut two 6”X6” beams 1 1/2” in length to join the cab sides together. Glue these beams to the inside of the cab walls. Cut 1 6”x6” beam 2 ½” in length for the center beam. This will give a slight overhang on both the front and rear of the cab. Cut ten 1 inch long scale 2”X6” planks for the roof. Glue them face down onto the roof beam. The roof itself is scaled corrugated roof material from Builders in Scale. I used Radio Shack PC Board Etching Solution to give the corrugated roofing material an “eaten with cancer” look to it. I cut the material to the proper length and width and placed them into an old cottage cheese container. Pour the etching solution into the container just covering the roof material. Within a few seconds the solution will begin to fizzle and get warm. Keep a close eye on the roof material. As soon as you get the desired effect you are looking at, fill the container with tap water to stop the etching solution from reacting to the roof material. Remove the roofing material and allow it to completely dry before gluing them onto the roof. I used an Exacto knife to cut a few more holes for a very worn out roof. Do not glue the cab to the floor just yet. The side, front, and rear side frames, or walls if you please, are made from the 2’X6” scribed siding. I cut them to a height of 3 boards each and used scale 4”X4” posts for the uprights. Finish the top of the walls with a 2”X6” across the top lengthwise. With the cab dry fitted to your preference of location, measure and cut the length of the sidewalls. On the model pictured the front walls are 2” in length and the rear walls are 1 3/8” in length. Once you have the side boards made, glue them in place but do not glue on the cab. Finally, install NBW castings onto the side frames in the appropriate place. The Trucks At the time of this article, Boulder Valley Models makes an excellent set of side frames for their Dunkirk model. Unfortunately, these frames are not available separately. Perhaps with enough interest this will change. I can only recommend that you visit his website and e-mail your interest in the side frames and save yourself this step. If not, you can dress up the existing frames as I did. Begin by gently removing the frames from the power drive trucks by gently pulling the frame straight off. You may need a small jewelers screwdriver to help pry the side frame off. Be careful that you do not break the round insert tab from the frame. With a pair of spru cutters, remove all of the brake shoes and components so that you have only the frame and journal box covers left. You can re-install the frame at this point. I had an old pair of HO trucks in my junk box. I removed the journal box covers until I had just the spring box left and glued those onto the center of the side frames. This gives the side frames a little better visual appearance and helps hide the freight truck look of the existing SW 7 side frames. Final Assembly Painting, Weathering and Final Details Now it is time to paint the boiler and water tank. Painting and weathering is to ones’ taste. You may have your own ideas and by all means, feel free to paint and weather as you see fit. I will explain how I painted and weathered my model. Begin by painting the boiler and water tank flat black. I used Wal-Mart flat black paint and applied to light coats to the boiler and water tank. I also painted the inside of the tank as I used a white 35mm case instead of the black one that I recommend. Next, I used Bragdon Enterprise chalks and applied them and used Krylon Matt Spray to seal them onto the boiler and water tank. Next, I installed the bell and whistle. Glue the water tank onto the water tank stand. Once you have finished, you can now glue the Climax floor onto the SW 7 and glue the boiler and water tank fixture in place on the Climax floor. At this point I installed the couplers added one more 6”X6” beam to the front and rear end beams and notched them to fit around the coupler pocket. Next, I made the front and rear running boards from 4”X4” beams with a 2”X6” foot board. Glue those in place and install NBW castings appropriately. Next, you need to rust color the corrugated roof material. I used Bragdon chalks and used a few shades of rust color to add texture and color variations. Again, I sealed this with the matt spray. When the cab is completely dry, glue it on the Climax floor. At this point I dusted and sealed the entire model with various shades of chalk to give it a hard, weathered look. I cut up some Sage brush to use as wood for the fuel for the Climax, and glued it in the areas shown. Finally, I added some chain, lube cans, tool boxes and tools to give it that well used look. As to the price, I want to say she was under $75.00 total, including the drive mechanism! This project gave me a lot of satisfaction in building everything from scratch and creating a backwoods looking model and I hope you will try to do one too.