Based upon the recommendation of another member here, I ordered the VL sound box car, and it is great. The truck without the electrocoupler seems to have all of the problems the first Vietnamese trucks on the milk cars suffered from: metal couplers that will couple to existing rolling stock, articulation so the car doesn't derail on curves, and it's sprung.
I'm hoping these become the standard truck for rolling stock going forward. In fact, I would like to get some of these for replacement on my milk car and two plug door reefers. Has anyone tried using these as replacement?