Your mods are great as always, I do have some notes to add though you may or may not have experienced this yourself.
Some of the cars esp the double bogie sets on the heavy duty flatbed have a long enough overhang from the bogie that causes the fixed coupling on the body of the car to create a pinching point between cars on tight turns, when attached to the trains they can very easily derail. If the coupling instead was fixed to the bogie or allowed to flex from the car this problem would be reduced or eliminated. Also for the double bogie it would have an easier time on corners if each bogie rotated independently and both were attached to a frame which in turn pivoted from the car, like how it would be setup irl.
Adding compatibility for other containers to the well cars was also very easy, increase the width size of the cars slightly and change the attacher and they work - at least connecting them. Not sure what the solution will be for containers of varying heights, I changed the second attach point to be @3.255 which is good for the high cube containers from hispano but has a gap for other container sizes. If you want to unload those containers directly from the car to a trigger point on the ground though his container trigger point is set too low. It would require you to raise the height of the car or for him to update the container mod and raise the height for some of the triggers. Everything works fine for me with those changes but I’m sure many others would love to do the same.
