Because cars get tyred but trains do not, with the exception of Rubber-tyred metro systems.
A COW-asaki MOO-torcycle!
They couldn't fit a deer into the car.
Because of the conductor.
One says, "Spit out your gum!" The other goes, "Choo Choo Choo"
A-tyre
Because there is no try.
They're both under DC.