Hi there!
First I'd like to start with saying I absolutely love your mod, in fact its the only reason I started playing Factorio again.
I've been using the resource/Id combo as following: [resource] [amount of wagons]. I choose this method because I might require larger loads once I progress towards a larger base.
Luckily you've provided a couple extra icons (extended through another mod) for the empty trains, which use the [empty resource] [amount of wagons] as their respective ID.
Right now I've advanced to the more expensive materials, of which I don't want a full train to be loaded but unfortunately this is seems impossible to arrange with the current setup. When selecting a count it will use the ID of the resource, however in my case these make no sense for empty trains.
My suggestion would be to let you choose the resource when setting a count, if this is the resource ID by default it shouldn't introduce any breaking changes.
Here's an image of my setup: https://i.ibb.co/1mkQLSZ/tsm-request.png
Thanks again for your amazing work!
