The way I do it is find a suitable wagon place it on the track in surveyor, click on the ? in the locomotive tab and click on the wagon which will open it.s commodity window, if it can be loaded and unoladed. You will see at least one row of commodities with a number top right which tells you how max amount of pruduct it can carry in that row. Find a row with a number that suits your needs and click on the + which will open the commodites window. Select the commodity you want it to carry and then click on load which will allow you to see it loaded on the wagon. Once you are happy with your choice set up the numder of wagons you need to carry your commodity either empty or loaded.
Just remember that instantload will load the default product if you use this command.
Now the best way is to DL hert CSX lumber 8ft flat car and clone it change the kuid # of the lumber 8ft to the kuid # of fruehauf & change the name in the config file.
Now this car will only load fruehauf.
You should be able to load the Fruehauf on any of these:
BNSF Flat car 917504,<kuid:46162:15004>
50ft up flatcar 06,<kuid:58422:100254>
MILW-Flat-50ft-L-07,<kuid2:82412:300120:1>
MILW-Flat-50ft-03,<kuid2:82412:300119:1>
TOFC 89ft FlatCar TTX1,<kuid:126855:100891>
