Unnecessary Train Journeys

Issue description

Two train stations on a network: one loading hydrogen, unloading water the second loading water, unloading hydrogen.
I expect: trains at first station to unload water and load hydrogen, go to second station, unload hydrogen and load water, go to first station, repeat.
What happens:
train at first station loads hydrogen goes to second station, unloads hydrogen, goes back to first station, goes to second station loads water goes to first station unloads water, goes back to second station, goes to first station, repeat.

Reproduction steps

Set up train network and watch.

Game version and build number

v0.8.4b b593

Operating system

Windows

You should post screenshots of your train network and station pages, and the stations themselves to show exactly what you are doing, there are all sorts of things you could do that would cause unnecessary trips in your train line and networks, even if the game is capable of having a train do this task without splitting the stations up.
I would also personally suggest using a train LINE rather than NETWORK. You might be able to get a line to run the unloading and loading the way you want, but I wouldn't expect a network to handle this task gracefully without some extra settings that are not available.