I recently picked up a pair of Atlas 89' flat cars in 3 rail that I wanted to convert to 2 rail and lower them in the process. I ran across Mike DeBerg's thread on lowering Atlas 89' flat cars (wow - 11 years ago!). Mike lowered his cars by removing the top bolster support and grinding down the bolster pin on Atlas 2 rail trucks. Since I had to source 2 rail parts I decided to try a set of Kadee #753 trucks.
The first step was figuring out the solution using the parts provided. Kadee provides a pair of Atlas adapters and a truck bushing with the trucks. Since I was lowering the car, I chose to use the truck bushing as the bolster, but had to drill it out to 3/16" ID so that it would fit over the metal Atlas mounting stud. The bushing shoulder provides about 3/32" of clearance above the mounting boss. I stepped up the drill bit sizes, but holding a round object while drilling out its center can be a bit tricky on the last bit. Here's a picture of the stock bushing (top) and a butchered but mostly functional bushing with a new inside diameter of 3/16" (bottom):
Next is a picture of the truck installed using a #4 washer (3/16" OD) and the stock Atlas truck mounting screw. I also added Kadee #746 type E long prototype head centerset couplers by drilling 1/16" holes and using 2-56 x 5/16" screws, mounting directly to the underside of the deck as Mike did. This raised the coupler by about the same amount as the Kadee trucks dropped the car:
Here's a comparison between a stock Atlas 2-rail car (left) and a converted 3-rail with Kadee #753 S-2 trucks with 33" wheels. Note the difference in height between the rail and the spine of the flat cars, and the gaps between the bottom of the deck and the wheels. The coupler height is close or the same as the stock 2R car after the modification:
The flat finish of the wheels, trucks and rotating bearing caps along the lower stance really enhances the look of these cars:
Have a good weekend!
Tim
I'm thinking about creating a sprue full of shims of different sizes that could be 3d printed. So keep track of the shims you're using.