California's Railroad to the U.S. 1861 - 1996

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Model Train Help EBook

Kitbashing an SP Rotary Snowplow

with Scratchbuilding the Cut Extension Wings

© 2007 David Reed

To start my project I followed what John Buffalo did in his article in Prototype Modeler, April 1979. I started this project in 1981 and finished the first plow in 1985, just in time for a NMRA Regional Meet in St Louis, Mo. I did not follow the article word for word and did what I thought was more research to do a second plow, following his plans to do #208. The windows in the cab door are also round, not square as his plans show, Also take note that plows #204, 205, 208 and 210 do not have the wing extensions, which I did not know when I started my second plow. I will have to modify my shell or start over. Now that I have looked at Richard Percy's Web Site, I see the plows have two air tanks, one on each side. I still am not sure if my windows on the fireman's side are right I also question the length of the plow, so as you build your model, you must use your own judgment or do more research. We all learn from mistakes.

All gluing was done with either a liquid plastic glue for plastic to plastic or ACC for metal to plastic or in the case of the wing assembly, Nylon to plastic. For body filler I originally used Squadron Green, till somebody suggested auto body putty. It has less shrinkage. To begin construction, you will need 2 Athearn plows, one for your model and the other for parts. The body will require 2 cuts. First cut is made 16 ft from the front of the cab. The second cut is made 20 ft from the rear. You will now have a body 36 ft. long. If unsure about your cutting ability, cut a little long and file down until you get the right length. The frame is cut differently, so the cuts of the shell do not overlap each other. The first cut is 22 ft. from the front, measuring from the rear of the blower housing (not the metal weight). The second cut is 14 ½ ft, from the rear of the frame, making sure to measure to the tabs on outside end of frame. Please ignore my truck spacing, as Richard's photos show where I made a mistake on truck centers. Truck centers should be 20 ft center to center.

Now that all cuts are made to the frame and the shell, let's start by putting the frame halves together. I used Plastruct angle material to square the frame on the sides and bottom with sheet styrene in between. With this done, set the frame aside for now.

Before we assemble the body halves together, you will need to sand and or file the body halves completely smooth. Remove all rivet, window, grab iron detail, etc. Be sure to leave all ladders hanging below frame in place, and when you cut the 3 ½ ft x 8 ½ ft section, leave that ladder in place too. With the body halves sanded smooth, start filling in all unwanted holes and doorways with plastic scrap and body filler. For putting in new windows, so they arrange correctly, drill a 5/32 in. hole in the new location and finish filing opening to proper size. The front door windows will need to be filled if you want the smaller windows then drill new windows with 1/8 in. drill bit. Note that the fireman's side has a second door at the back. You will use the second shell and cut the door out of the same side. I cut an area around the door 3 1/2 ft. x 8 1/2 ft. Using photos from Richard's web site, measure in and cut an opening 5 ft. from the rear of the shell, 3 ½ ft. x 8 ½ ft. for new door. The back of the shell also is sanded smooth and filled with body filler. The back end will get a new door from an F7A or B unit end. The back also gets 4 MU hoses on the engineer's side and a Detail Associates uncoupling lift bar #6240.

When all body work is done it is time to file the front window openings square. The 2 side windows are 2 ft. square. The front windows are 1 ½ ft. wide and 2 ft. tall. With the body sanded smooth and all windows and doors in place, its time to put the 2 body halves together. Remember to leave about 3 ft. at the bottom of the shell without a plastic seam support so it clears the frame. Fill the body seam with body filler and sand smooth until it all blends together.

The roof does not have a lot of detail. There is a skyline casing on top. I based the design on the flat roof of the plow cabin. The casing is about 16 ft. long. Mine is 22 ft long, a little too long now that I have seen more photos of the rotaries in the yards. I used sheet styrene and Plastruct #90006 angle. The angle is laid so the closed side is down, to get the side slope. There are 2 square panels behind the skyline casing, they are about 3 ft. x 3 ½ ft. I used the plow roof walk flipped over and sanded it to fit the roof profile. Photos help in placement of these panels. Install lift rings and grab irons where appropriate. There is a short roofwalk down the center of the roof, from the casing to the end of the plow, I cut the Athearn plow roof walk to fit this location. On the back of the plow there is a small roofwalk gang way.

On the engineers side at the back of the plow is the steam generator. You need to drill 2 holes where the main components of the steam generator go, and make a level platform that comes just above the roof line. I made mine from plastic tubing. Mount the round steam generator intake (the bigger round one) towards the access panel and the exhaust up and behind toward the rear. The little rectangular part I put above the intake. There are shields protecting the generator from flying snow. I used brass tubing ¼ inch and 7/32 inch in size. The intake one I cut out the rear third. The roof of it is made from a round roof hatch from an ACF covered hopper from Athearn. The smaller one the tube completely covers all sides, there is an open area above it and then a roof. I used brass wire as a support to hold the roof up. The roof itself is out of my scrap box. It's conical in shape and I think it came from a Roundhouse kitbashing kit.

Detailing the shell is the final step. I do not remember what size wire I used to make all the grab irons. It was larger in size than Detail Associates #2202 grab irons, maybe size #78 wire. You will need to bend these to fit the location where they go, using photos as a guide. The door openings grabs are 7 ½ ft. long. On the rear engineer's side there is another set. They are 5 ft. long. For the steps to the cab, I used grab irons, but they look more like metal steps looking at photos on Richard's web site. There is also grabs around the front windows. Below the front side window there is a small walk gangway going to the blower housing. I made mine from Plastruct angle 1/16 x 1/16 in. and about 3 ½ ft. long. There is a ladder at the back on the fireman's side, I used Detail Associates 7 rung freight car ladder. A round fuel gauge goes on both sides of the body above the air tanks, Detail Associate #3101. There are 2 small grilles high up on the sides of the plows. I used an AHM GP18 shell for these grills. The grilles are the air intakes high on the hoods. Life-like or Atlas shells would work as well I believe, other than that I do not know what else to use today. Any other details I missed that you feel you want, go ahead and add them. PHOTOS MAKE THE DIFFERENCE!

The underframe does not have a lot of detail to it, there are only 2 air tanks, one on each side. Make these from the air tanks on Athearn's SW7 shell. It will take 2 shells for the air tanks. The only thing left is brake detail. I used AB brake detail from my scrap box. I used scale chain to hang from the trucks to the frame, leaving it long enough so there is play and swing in it. The frame also has the blower housing, so if you are not doing the wings, you need the light and its housing. For the light I used Detail Associates #1002 and for the grill I used Athearn observation railing and scrap plastic.

All that is left is painting and decaling and I will not get into painting and decaling as that is straight forward and everybody has their own way of doing it. UNLESS you are building the wing extension, in that case DO NOT PAINT THE UNDERFRAME, you may paint the rest of the body if you wish to. Otherwise wait till you have completed the wing extension assembly.

The paint colors are Engine Black, Reefer White, and SP Daylight Red. You need to paint the bottom third of the wings and blower housing Reefer White and the fan blade SP Daylight Red except for the center 3 ft, that you brush paint Engine Black. The rest of the plow, including the rest of the blower housing is painted Engine Black. The decals used are Micro-Scale #155 SP MofW set.

Windows are the last thing to do when all paint and decal work is done. The side windows are Detail Associates #1711 14 ½ in. lenses. The small door window is Detail Associates #1710 12 in. lenses. The cab side and front windows are made from Athearn passenger car windows. You will file to fit each window, it's trial and error since each one may not be exact. They fit flush to look like a sealed window. I used liquid plastic glue to glue the windows in, but you can also use Micro Krystal Kleer by Microscale. There might be something better today to do the windows; I just had the window material in my scrap box.

outline drawing of rotary snowplow 62k
example of an Athearn decorated snowplow kit
image of finished Snowplow model
image showing where to cut the body
image showing two body sections engineers side
image showing where to cut the body
image showing two body sections firemans side
image showing where to cut the frame
image of finished Snowplow model
image showing rear detail and fireman side rear door
example of an Athearn decorated snowplow kit


  • Athearn
    • 2 Snowplow Kits #1194 undec (listed as discontinued)
      you don't really need the new plow and tender kits as these are the older steam powered type...
    • passenger car window material
    • 2 SW7 shells
    • Observation Car Railing

  • Detail Associates
    • #1002 Oscillating Dual Gyralight
    • #1508 MU hoses
    • #1710 12" small round lens
    • #1711 14 ½" large round lens
    • #2202 Grab Irons
    • #2206 Grab Irons
    • #6240 Coupler Lift Bar
    • #6242 7 Rung Ladder

  • Details West
    • #118 Steam Generator Set

  • AHM GP18 shell, Atlas GP7 shell, or Life-Like GP7 or GP9 shell for the small intakes at top of hood

  • K & S
    • #130 7/32" tubing
    • #131 ¼" tubing

  • Plastruct
    • #90002 1/16" angle
    • #90006 ¼" angle

  • Paint
    • Engine Black
    • Reefer White
    • SP Daylight Red

  • Decals
    • Microscale #155 MOW set

Plastruct or Evergreen sheet styrene to match thickness of skyline casing to match cab roof line.

Kitbashing an SP Rotary Snowplow

Cut Extension Wing Construction

© 2007 David Reed

Model Rotary Snowplow Cut Extension Wings

(1) Construction of the 4 ft. x 10 ft. wing extensions is involved. The wings will actually be about 4 ft. 3 inches long, just to get an angle on the front of the blade. Take your time and they should come out fine. Some of the construction is trial and error fit. My construction methods may not be the way you want to do it, which is fine. I am not sure if the way I tell you to do it is the exact way I did it 23 years ago.

(2) You will start construction by building the wings themselves. If you can, build both wings at the same time. Each wing will take 3 Dubro #166 hinges. The end that gets glued to the Blower housing is cut back to the first set of mounting holes on the hinge. After you have done that, cut the head off the hinge pin and take apart the hinge for the next step. The top hinge will have a 1 scale ft. cut off, the middle hinge will be a complete hinge, and the bottom one will be half a hinge. (Use photos to see how I cut these sections).

(3) You will use 1 ¼ inch long dressmaker sewing pins to hold it altogether. This becomes part of the hinge as you complete the wing construction. Clean up any nylon burrs and sand or file smooth the Dubro name off the hinges themselves. Once this is complete, use Evergreen Styrene #9010 B plain stock .010 thou thick. Cut the styrene 5 scale ft. x 10 1/2 scale ft., so that it is oversized. You will cut 9 scale inches off the width to make it 4ft. 3 inches, except at the bottom. At the bottom, you will leave 1 scale foot on, so that the bottom foot is 5 scale feet long, to fill in the gap, left where there is no hinge, to complete the look of the plow wing. You will need a filler between the styrene at the back end, where there is no hinge.

(4) Using ACC glue, square the styrene on the top hinge, making it flush against the hinge movement, using the glue sparingly, so you don't get any in or on the moving parts. Work your way down each hinge until you are at the bottom, put the styrene in place, cut to the size it needs to be. When you have completed gluing one side, cut off excess at the bottom. Now do a dry run on the back side to get a good, tight fit. Once the dry run looks good, using ACC again glue it to the back, the same way you did the front. Once you have the hinges covered in styrene, you need to bevel the front of the blades. There will be an opening at the front of the blades that will need .010 styrene #9010B used as a filler. Put a narrow strip in the opening about 2 scale ft. wide and 12 ft. long. Using liquid plastic glue to set in place. To hold the styrene in place on the front of the blade and get that bevel look, I used metal binder clips, (found in most office supply stores) to hold it in place while the glue set up. I used one ½ inch long and the other was ¾ of an inch long. Do any filling and filing on the wing to complete this part of the construction. Now do the same for the other wing.

(5) When both wings are complete, do a dry run with the narrow hinge to the blower housing. The wing is about 1 ½ scale feet from the top of the housing. Make sure that the wing assembly is above the top of the rail head at this time. If it looks good and you don't think it needs any filing, using ACC, glue the narrow part of the hinge to the blower housing, about 1 scale feet from the top and going down with the glue. Here again use the glue sparingly, so as not to get it on the moving parts, At the bottom, it will have no glue points. As you can see with my model, the wing bows inward. I have not thought of any way to correct this problem.

(6) After you have completed mounting the hinge to blower housing, remove the wings themselves, so that the outside of each wing can be completed. Use the center of the "T" section of PLastruct T-2 for locating on the wing, at the measured distance from the top down. There are 4 braces on the outside of the wing. The first one is located 1 scale ft. from the top, the second one is 3 ½ scale ft. down from the top, the third one is 7 scale ft. down from the top, and the last one is about 9 scale inches from the bottom of the wing. You will use Plastruct #T-2 1/16th T material, cut about 4 scale ft long. This is a trial and error fit to the wing. Before gluing to the wing, bevel the end that is away from the hinge.

(7) At this time, let's cut the sewing pins. This will aid in the construction and check the assembly as you build each part. The front pins are cut 1 ½ to 2 scale ft. long. The back pins are cut 2 scale ft. long. To assist in containing your small parts, I used small plastic containers, such as those that contain Kadee wheel sets. You will need one for each wing.

(8) Next parts to be put on the wing are Detail Associates #1102. It will take 6 of these per side. These are EMD nose lift rings. These are about 9 inches from the front end of the wing. First pair are about 1ft. 3 in. and 2 ft. from the top. The second pair are 5 ft. and 5ft. 9 in. from the top. The final pair are 8 ft, and 8 ft. 9 in. from the top. Mount these so that they are parallel to the rail head, with the rounded short end away from the cab. To be sure there is clearance for the 3/32 square tube, have it handy to check the space between the lift rings.

(9) Next step is cutting the K&S tubing to the proper length. You will cut the 1/8 in. square tubing #18151 2 scale ft long, you will need 6 of these, 3 per side. Next cut the 3/32 in. square tubing #1503 4 scale ft. long, you will need 6 of these, 3 per side. After alI tubing is cut to size, clean up all burrs, especially where the tubing is going to slide in and out of each other and where the Athearn stanchion will go in the 3/32 in tubing. When the K&S tubing is all cut, the next step is to take an Athearn stanchion, bend the handrail loop over a sewing pin so it fits, but not too tight Cut the stanchion 2 to 3 ft. behind the loop and using ACC glue, glue it into the 3/32 tubing, being sure to get the loop down at the end of the tube.

(10) Next step involves the 1/8 in square tubing. The 1/8 in tubing is cut 2 scale ft long, on the top and bottom of this you will ACC EverGreen styrene strip #133 .030 x .060, cut 2 ½ scale ft. long. Bevel one end down, for a transition taper. You will glue the last foot out to the bevel on the end opposite the stanchion. On top of this, opposite the bevel end, you will glue Detail Associates #1103 lift rings to the styrene strip and file to equal width. The end of the styrene will butt up against the mounting hole rim. You will make 3 pairs of these per side. A WORD OF WARNING, THE BOTTOM ONES ARE NOT MADE THE EXACT SAME WAY. The Detail Associates #1103 is angled back at a 25 to 45 degree angle, caused by the low mount point at the blower housing. I would recommend waiting till you get the blower housing mount on, before doing the bottom one on both sides.

(11) The mounting plates on the blower housing are as follows. The top two are made with Plastruct I-beams 1/8 x ½ x 24 inches long material. File the I-beam itself off on both sides till you get a flat surface. Measure 2 ½ scale ft, and make a cut. You will need 4 at this length. The bottom one needs to be cut 1 ft. 3in. wide and 2 ½ feet long. You will have 2 of these.

(11a) Start with the middle mounting plate, as this one is 90 degrees to the center arm. The other two sit at a different angle. I would suggest doing the top plate next and follow that with the bottom plate and its assembly. Build each mounting plate one at a time. It will help when lining up the arms, so that the drum for the Dubro hinge is at the right position when attached to Detail Associates #1103.

(12) Assemble Detail Associates #1103, #2801 and the actual nylon hinge drum cut off the hinge plate of the Dubro #166 hinge. You need to use that part to have a good fit for the sewing pin to pivot in, You also need Plastruct T-shape # T-2 1/16 in.f almost 1 scale ft long and bevel the outside or end at an angle. You will need 12 of these parts.

(13) Enlarge the hole on Detail Associates #1103, so that it can take Detail Associates #2801 in the enlarged hole. Detail Associates #2801 has a big end on one end and a smaller end on the other. Cut off the big end so that you have a flat plate and then a round drum. Insert the small end of Detail Associates #2801 into the hole on Detail Associates #1103. Do that with the other 5 as well. When that's done, using ACC, glue the nylon pivot from the hinge onto the other side of Detail Associates #1103.

(14) When these subassemblies are complete, using the photos and drawing, glue each of these parts to the 1 ½ ft. x 2ft. plate.

(15) Start by gluing Detail Associates #1103 with the other parts attached, to the plate, centering it on the plate. After these are attached, glue the Plastruct T-shape on either side of the lift ring.

(16) The bottom plate is done the same way, only the plate is 1 ft. 3 in. x 2ft. If you have not completed the bottom arm, now you can, and check to see how to fit Detail Associates #1103 onto the arm, to get the right angle. After all parts are completed, assemble them and see that there is no problem with the moving parts. If there is a problem, now is the time to correct or rebuild where the problem is.

(17) With the wing assembly complete and if everything is working properly, let's add the final detail parts to the blower housing.

(18) The tender brake cylinder from Cal-Scale #BC-221 is mounted to a piece of EverGreen styrene #90108 .010 thick material, cut to same size as the bottom of the brake cylinder base, 1 ft. 3 in. wide and 1 1/2 ft. long. Glue the brake cylinder to the styrene with ACC. To the bottom of this add Plastruct angle shape #90003 3/32 in, in size. This is cut 1 ½ scale ft. long. Glue this to the bottom of the plate you just completed, putting the angle facing out. Before gluing to the blower housing, trial fit where it goes at the top of the housing, mark where the rod hits the housing, so you can drill an appropriate size hole, I do not remember the size, but I think it's a #75 drill bit.

(19) The headlight is the next part to be made. The grate to protect the light is the Gate Railing from an Athearn Observation Car. With the top railing frame removed, the plate at the bottom becomes the platform for the headlight. Glue this on top of the blower housing and the back, bottom of the plate rests against the blower shut pivot. Make sure you have it level. Make sides out of the .010 styrene as per photos. Detail Associates #1003 is the headlight used. Do Not Glue this to the platform, if you do, you cannot put the light jewels in their mounting holes, You will hand paint this part and install it with the jewels after the blower and frame are painted.

(20) The final part to be made, is the coupler and its mount on the front of the plow. The coupler itself is a modified Kadee #5. My towing bar is made from a paper clip, bent and cut to fit the inside of the housing. I used F-unit nose lift rings, Detail Associates #1102, glued in sideways, with the rounded part out, at the proper height for coupler. I have noticed with Richard Percy's site that some used a rather large bar. You decide on your own what you would like to do here. There is an air line you may also add.

(21) Painting is all that is left. The brass tubing for the arms are blackened with A-west product called Blacken- It. The part number for it in the old Walthers catalog is #158-2. Paint the lower third of the wings and inner blower housing Reefer White and the blade SP Daylight Red. The rest is painted Engine Black.

(22) For those that do not wish to have the moving wings, but wish to have static wings, you can glue the movements in place.

general arrangement drawing of cut extension wings and hydraulic actuators 131k


  • Detail Associates
    • #1003 dual headlight late type
    • #1102 F-unit nose lift rings
    • #1103 lift rings flat mount
    • #2801 brake cylinder

  • Athearn
    • Observation railing
    • locomotive stanchion

  • Dubro
    • #166 nylon hinges

  • Cal-Scale
    • #BC-221 tender brake cylinder

  • EverGreen Styrene
    • #9010 B .010 thick sheet styrene
    • #133 .030 x .060 strip styrene

  • Plastruct
    • #90003 3/32 inch Angle shape
    • #T-2 1/16 inch T shape
    • #? 1/8 x 1/2 x 24 inch I-beam
  • K & S
    • #18151 1/8 inch square Tubing
    • #1503 3/32 inch square Tubing

  • A-West
    • #158-2 Blacken-lt (not listed in Walthers catalog any longer)

  • Miscellaneous
    • Paper clip
    • 1 ¼ inch dress maker pins


  • Prototype Modeler April 1979 page 9 - SP Rotary Snowplows, short history.
  • Prototype Modeler April 1979 page 11 - SP Rotary Snowplow conversion.

This article gives two choices, those for modeling SPMW 204?, 208 or 210, or SPMW 205, 206, 209, 211, 220 or 221. The article does not include any info to model the cut extensions or wings, which is unfortunate, as photos show the wings were fitted (to some) in the steam era, and the article is from 1979...

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website logo for use in banner exchange [185 x 50] (5k) This document prepared and maintained by Richard.A.Percy.
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This document © 2007. Richard.A.Percy