An Atlas 42' coil steel car and an Athearn articulated auto rack

These two conversions are both fairly easy:

The coil car is a straightforward URS retro-fit with a medium length shank:

The only modification I made was to add a 0.2 mm truck washer to bring the coupler height up to spec. The washer may be found here.

The auto rack is equally straightforward. I screwed a scale box with a short shank directly to the car's floor:

I lined up the front face of the box with the end of the car:

The short shanks work fine with 18" curves. If you have sharper curves, you may need to go with a medium shank. At some point long ago I swapped in MTL truck-mount couplers to bring the car spacing closer than with the stock Athearn couplers. The coupler height is perfect with the MTL trucks; I'm not sure what it would be like with the stock Athearn trucks, but it's probably fine.