Class I is a lot smaller than it was when I was young.
Florida East Coast would be Class I if revenues were consolidated with the transportation assets of its parent Groupo Mexico. I don't know that you could get there with just the FEC (Class II) and Texas Pacifico (Class III) assets in the US, but if so, it would be shorter.
I don’t know if Class I is getting smaller, or the industry is just changing. I think a Class I railroad today has at least $250 million of annual revenue in 1992 dollars. It’s possible the current railroad business model makes it a bit easier for smaller railroads like the KCS hit that threshold.