Upon my single player adventures, I came across a need(Well, I guess you could say this was more for fun than neccesity), to smelt many items in a very short time. Such a device required many furnaces, hoppers, and rails to say the least. However I needed a way to collect all the items after there were smelted, and so a circular track with a hopper cart was born. The only problem after that was a station needed to be invented to stop the minecart and unload it completely, before sending it back, and so, the MUSv1.0 was born(Minecart Unloading Station version 1.0).

The MUSv1.0 can:
1. Stop a cart above a hopper
2. Unload it fully
3. Send it back along its way when it is empty
4. Keep the minecart at the station in wait

If you download the file I have left instructions on how to use the station and how the station works in a chest. Enjoy! 

Note: The track I made is tiny, however it is just an example of a cart going out, collecting imaginary objects and returning.