Minetest is an infinite-world block sandbox game and a game engine, inspired by Infiniminer, Minecraft and the like.
The community is about the great and open source sandbox game writed in Lua, Minetest.
Feel free to call players for a multiplayer game or publish your project of a mod and everthing related.
Download the game. Check out the wiki.
I've tried the standard Minecraft one and several variations of it, but none work. The standard one below just doesn't give the cart enough time to unload. I tried placing 3 hoppers in a row and one in a closed track circuit, but those didn't work either.
Standard
Circuit
I decided to give this a go. This is what I came up with:
It has the usual consistency issues of mesecons/voxelibre-redstone, but seems to work the majority of the time. It won't return empty carts though, so make sure to send them in with at least 1 item.
Edit: much simpler version:
(Remember to right click the second comparator to put it into subtraction mode)