Some of my latest paint jobs have been a #216 hopper and three # 116 ballast cars. All of them came out great but needed loads to look complete. Since I figured my chances of ever finding the Lionel load inserts for the #216 were slim to none I made my own. Using 2 pieces of 1 X 4 and some cut down brackets left over from some horizontal blinds my wife made me install years ago I managed to produce the following for the 216.
I think these actually look better than the Lionel part.
For the #116's i used a piece of 1/4" plywood and 4 dowels for legs as shown below.