If Carter isn't meticulously "parking" cars in a row down the entire hallway, he's driving them around making engine noises (including sound effects for gear changes and squeaky breaks).
If he's not doing that, he's orchestrating car accidents with his various ramps and train track pieces. When they collide, he says, "OHHHH! Train trash!" or "OOOHHHH! Car trash!" (trash = crash).
If he's not crashing cars, he's talking about dump trucks, tractors, and train tracks, asking for Nascar while pointing to the TV, or reading books about excavators and helicopters.
If he's not doing any of the above, it's because he's eating or sleeping (with a HotWheels car clenched in his fist under the blanket, no doubt).
And the first thing he says each morning is, "Hi Momma! Trains?"
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