Class 1 — explosives

Class 1 is explosives. The diamond carries a 1, and usually a division such as 1.1, 1.4, or 1.5, because those divisions behave very differently. A 1.4 shipment and a 1.1 shipment are not the same kind of risk, even though both are class 1.

You will see class 1 more often on boxcars and specially assigned equipment than on ordinary chemical tank cars. The compatibility letter, when it is shown, groups explosives that may be carried together. It is part of the placard, not decoration.

Don't crop a photo so tightly that the division disappears, and don't guess the division from the orange color. Write down the full marking. If you cannot read it, say so.