MAC Distribution #35003
Soviet Truck BA-20SD Railcar
1/35
Trying to build this model in seven days for Workin’ on the Railroad 2025
Already questioning this endeavor with the rear differential assembly design. How to keep this from a wonky three wheel stance.
Courageous build Ko! Always wondered why “Limited Edition” - limiting brickbats? I’d suggest mocking up some rails you know are straight/level, then put the chassis with dry-fit wheels on it, put a sympathetic weight on top and then glue the wheels. That’s of course assuming the chassis ain’t warped, maybe hot-hair-dryer-blast the assembly while it’s in situ?
Good idea with the track. I have 1/35 track already built and the chassis ain’t warped.
I guess the Limited Edition refers to the added rail traction wheels? They are in a separate baggy in the box. I just realized that I need to confirm if this is European gauge or Russian gauge…
Good point - depending on your accuracy-quotient, whatever the wheel-gauge is may not be noticed if it turns about to be Euro-width. But surely if the manufacturer is of an Eastern persuasion they gave it Russian gauge?
Since the originals were produced alreday in 1938-1939, i.e. before Hitler attacked, they would have been on Russian gauge tracks.
Russian gauge is 1520 mm → 43.3 mm
Standard gauge is 1435 mm → 41 mm
The gauge is measured between the rails, inside to inside, i.e. the surfaces that the flanges shall not quite rub against.
Typically refers to the number of kits produced. If that is true or just a sales gimmick I am not sure.
“Correctamundo”, it is Russian gauge. I’m going to try and convert to Standard gauge by A - trim off the axle ends. Then B - shave down the wheel thickness from the inboard side. I think I can remove a total of 2.3 mm if this is done to both sides.
Top picture: Four on the floor in Russian gauge.
Bottom picture: After axles were shaved down at the ends and shoulders. The wheels now installed further inboard to Standard gauge.
Nice shave! … 
—mike
Thanks Mike @justsendit.
More shaving under this part to get the chassis part to fit (arrows). the center locator hole is too far forward to properly receive the locator pin on the chassis part.
This is the current status of the BA-20SD Railcar:
Axles reduced to Standard gauge.
Armor body panels cemented together to the best they can fit and just sitting on top of the pan part.
Tamiya Thin will cement the black styrene - chassis parts - but will not cement the green styrene from this kit. I had to go to my LHS to pick up these heavy hitters for that.
Fumey
See how the armored body assembly foot print is too narrow for the bottom mating part. I glued in styrene blocks to spread out the bottom of the armored walls. This works but I have to hold the two halves in place while the cement cures. Which means I have to have all the interior painted and assembled prior to that. Don’t have this problem with the Hobby Boss kit because it’s one piece. So I fabricated a spreader pole from sprue from the same kit. I’ll make another one to install in the engine compartment. This way I can dry fit assemble this top half in place to work on the interior later.
I may be imagining things but I get the impression that the side walls on your model are too vertical.
I don’t think that brute force along the lower edges will fix this.
If I were in your situation I would split the seams on that armoured body, sides to “radiator grille” and sides to rounded rear wall.
Front view:
Rear view:
Front 3/4 view:
Getting it all together after the surgery would require 4 styrene wedges, 2 by the sides of the “grille” and 2 by the sides of the curved rear wall.
This one seems to have more vertical sides. Different factories or production changes and MAC thought they were all the same and mixed the measurements??
Finnish parade 1941 with a captured and reused BA-20, also sloping sides
Disassembling the armor body parts would be extending beyond my interest in such things especially since getting all the panels assembled in the first place was no stroll in the park.
I don’t know if we can blame MAC alone on this error since it’s placed around 10 years later on the ScaleMates timeline. https://www.scalemates.com/kits/mac-distribution-03-ba-20sd-railcar–185201/timeline
The angled armor has compound angles in the same part as well. I found that blocks work but - as you describe - are too stressful on the bottom edge so the “sprue bars” will work better.
I can count myself lucky since I got and built the BA-20 by Alan (different heritage line).
The later BA-20’s had a conical turret, the one by Alan has a turret with vertical sides
Thanks for all the research and help with this 
Nice save!
Cheers @Uncle-Heavy
The three view ports are flat and do not conform to the radius of the turret. I’ll leave these off and fill in the mounting cavities for these parts with putty and sand smooth.
