I picked up some of the latest run of these Lionel Husky Stacks this past year and they came equipped with the new design Lionel roller bearing trucks with the plastic bolster which allow you to purchase the Lionel 2-Rail 33" (70 Ton) conversion kit (~$20) to at least handle the truck part of the conversion to 2 Rail relatively easily. The coupler retrofit, as Mike Deberg shows above, is still not optimal as it requires some drilling, tapping and shimming for the use of a Kadee draft gear box. Please note; however, that the die cast "coupler pad area" on the end of the car only allows for drilling one draft gear mounting hole as the rear hole in the Kadee draft gear box lands right over an opening in the casting so the rear hole in the coupler draft gear box is not usable, e.g. draft gear can rotate side-to-side if not also glued in place. Also, that die cast "coupler pad area" is not that thick so not a lot of mounting screw thread engagement for that single lone coupler mounting screw. These cars are very well detailed and do make a nice addition to a modern era fleet but just need a slight tweak in the coupler mounting area to make them a fully universal 3R / 2R piece of rolling stock.
Scott