The Lionel KW Transformer was produced from 1950 until 1965. It generated 190 watts of power that could control two separate trains. It has an independent fixed 14 volt circuit for accessories, a built-in circuit breaker that triggers the red light on top when activated, and the ORANGE handle activates the horn/whistle circuit. There are two variations:
Variation A: The coil and lamination assembly is not riveted and there is no stamping on the underside of the base. Produced 1950-56.
Variation B: The coil assembly is riveted and it is stamped on the bottom "KW (R)." Produced 1957-65.
This transformer is preferred by many operators today due to the fixed voltage circuit.