Not realy complicated
I use these wagons a lot as I tend to run BR Steam 40/70s
I have these supplying the flour mill thats built in with 06
I looked in one of the activated grain wagons to see how it was done and copyed the bit concerning load/unload and comodities,
then cloned the LMS Grain Hopper and pasted the bit I saved in the config file
the wagon will now load or unload as required and the comodity in the industry is decreased or increased accordingly
there is no mesh involved as its a covered closed in wagon and the loading hatches do not open but the you wont see that unless you sit ontop the wagon,
but it goes through the prosess and the sound of grain coming from the shoots is there, , I have even repainted some of these and relettered them some are southern stock and some private stock, but like I said they are for my own use as I never asked permission.
as for the open wagon I have not tried this but there is a wood plank wagon ( clay I think ) that has a cover on in the loaded state and open in the empty state, I am sure the cover is just a mesh comodity so could be used on any open wagon just by playing with the config file,
I am a bit tied up at the moment on another project with some other guys but if I get time I will have a look,
"Kelly88" Its interesting to know that you can alter the config of the Grain Hopper to load up but it sounds like it might be Rocket Science to me.I"ll have a look though.One thing I definitely wasn"t going to do was to load Sugar in a Conflat (!) as Lincolnshire has its fair share of rain!..