TL;DR
When a condition for a train/platform is filling up, use a different color from when it is full. Not a gradient change like battery charge filling up for armor, a clear "filled or not filled" color change when finally completing.What?
It can be very difficult to distinguish a condition that is "almost completely fulfilled" from one that is filled, making it occasionally difficult to debug a train or platform's reason for stalling if it's near completion. Especially for newbies it can turn out that they set a ">" when they meant ">="This suggestion would make such issues very easy to spot at a glance.