Production Progression Visual
Currently there is no way to see when a particular building is not producing. There is a slight visual on certain machines that tells you whether it's producing or not, but it's not very straightforward what machine is held up in a production line when they are clustered close together. I tend to like my layouts compact, and having a visual indicator like a loading bar (loading bar full when the machine can't output) when clicked into the interface of the machine would help greatly.