These are two keystone plastic cars that measure just over 4.5″ long. The cars are transitions from the more complicated earlier cars and the use of Thomas produced plastic cars. The cars are identical to the earlier versions with two exceptions. The removable blue engine is gone and replaced with a molded engine. The second change is a larger hubcap with a Keystone K in the center. Note the black tires on the second car. This is the first time I have seen anything other than white tires.