I think I have the molds when I bought MEW. All machinery & tooling still stacked in the barn until spring. Harry
If you want to be truly innovative with your RichArt tooling, may I suggest that you create an entirely new car, specifically a "fish" car like the ones that many States used to deliver fingerlings from their State hatcheries to lakes and streams around the State. The "Badger" fish car seen below, was operated by Wisconsin and is typical of fish cars that several States operated. As part of the National Fish Hatchery System, Wisconsin operated two fish cars: Badger No.1 and Badger No. 2.
As you can see from the above photo, you would simply need to arrange the RichArt tooling to place cargo doors in the middle on both sides of the car and place small windows on either side of the cargo doors. Below the windows are aerated fish tanks filled with water and fish fry. In operation, the "fish" trains would stop along their routes in order to deliver milk cans filled with fish fry to waiting truck for further delivery to lakes and streams.
Here is a link to more photos on the fish cars that were part of the National Fish Hatchery System including interior photos showing aeration of the fish tanks. Most interesting!
For years I have suggested to MTH to produce "operating" fish cars which would load/shove milk cans into the beds of waiting State fish hatchery trucks. I'd buy several!