Refer to attachments, The blue minecart(with chest) is placed beside and one block higher than the red minecart(with hopper). So the problem is if i put any items such as i put some rails in the blue minecart, its getting sucked by the red one(minecart with hopper). Technically that should not happen. And because of this issue i cannot build a working super smelter using minecarts. Please fix this in the next update