Better loading schedule

[Václav]

I would like to ask for adding
1. Don't load any good
2. Load only selected good
into loading schedule inside line management.

And why?
1. Sometimes at end stations only unloading is wanted (but at this time I can only set 0% for loading - and so loadable goods are loaded to waggons if some ones are present - if any good can be transported via start station of train - but sometimes this is not wanted)
2. Sometimes (mostly in the beginning) are needed trains with waggons for more than one type of good. Then I would need to load all capacity for one good but I would not need to load all capacity of else one

[colonyan]

I like this one. Some time it happens unexpected and unwanted cargo loading.
This will help supply management.