My HO train set from the early 1980s had a Gulf oil tanker car that appears to be, I'd say, at least 54' actual scale. I pulled out my old trains after having them in storage a few decades and realized that I haven't seen an actual tanker car of this length since my childhood. I was curious if there was some change to the regulations that required tanker cars to be only half of this length. I have seen tanker cars since, but they have all been roughly half the length of the car that I have in my set. Just curious if the regulations have changed and these long tanker cars in the real world are now obsolete? I'd imagine one of these cars derailing could be catastrophic.