Add way to empty specific train cars in case wrong product is loaded

It would be nice if there were a way to empty a train car of it's cargo for use in a case where the wrong cargo was loaded.

When learning how to use trains people are absolutely going to have the wrong cargo loaded from time to time. We need a quick empty option for a unity cost. It's very frustrating to deal with otherwise. Sometimes there just isn't space to add an additional module or easily reconfigure a station to empty out the wrong cargo.
I tried testing a "catch-all" station which I could easily change to the product type I wanted unloaded but this seemed very wasteful and took time to reconfigure each time.
Instead, I've been sending the entire train to be scrapped and then recovered. Once in the train depot it can be rebuilt with the freshly emptied wagons just recovered - all with unity. Not a perfect solution but it is much easier than other methods.

New with trains, but we need this. Loaded the train wrong because I forgot the filters - Had to scrap the train and re-build it with the proper filters.
Please add the same system for "remove via Unity" we have for containers on train cargo wagons.