If a train and a car are traveling at the same speed, they have the same amount of kinetic energy

Probably not.

When two objects travel at the same speed, the one with the greater mass has
more kinetic energy, and the one with the smaller mass has less kinetic energy.

You haven't told us anything about the train or the car, but I'm pretty sure that
the train has more mass than the car has, so it also has more kinetic energy
at the same speed.