Tanker Wagon Label Plates
I noticed that, on the T1 Tanker Wagon's model, there is a fairly large flat metal plate on the side that looks clearly intended as a label of some sort. My suggestion is to implement this label plate so that it displays the icon of the fluid contained inside (and, if necessary, add a similar plate to the T2 tanker wagon). This will overcome a UI limitation of tanker wagons in that the player cannot tell at a glance what the wagons contain, unlike the flatcar and hopper wagons.