Chlorine gas is shipped in cars that are smaller than the LPG/Anhydrous cars. Also traveling down the SI in large amounts is Molten Sulfur, not a gas, in shorter tanks but still haz mat. Sometimes travels in solid unit trains (many, but not all, tanks painted yellow). Sometimes LPG moves from Canada to California during spring and summer to stock up for winter use. LPG is also used as a propellant in spray cans instead of CFCs and is injected into some plastics and fertilizers.