Here are some early fitted wagons to enable carriage of fast freight and differentiate between fitted and unfitted vehicles. I recommend that the existing unfitted wagons all be restricted to 50km/h (as I have done in Experimental) to give these vehicles sufficient differentiation.
Piece-Fast
Fitted goods van
Piece-Bogie
Fitted bogie goods van
Cool-Fast
Fitted food van
Cool-Bogie
Fitted bogie food van