Commodities not loading onto cars?

[YANRAYEESEDAY]

I recently purchased Trainz 22. I'm using classic surveyor mode to place and load cars. However none of the commodities will load. I can manipulate the loads of cars pre loaded in the session but not new cars. Does anyone know how to fix this issue? I thank you ahead of time for your help.

 

[OddRails]

I'm not very good with details, but does it help if you save the route or session after placing the railcars?
Then load them after the save?