The Lionel 1053 Transformer was available from 1956 until 1960. It generated 60 Watts of power and would control one train. It does not have a built-in circuit breaker, but after 1957 Lionel would offer the No. 91 Circuit Breaker that could be used with this transformer. It came with a horn/whistle control button. The "X" printed on the box illustrated above indicates that this transformer was originally included in a set.
A veiwer of this page has stated that his No. 1053 has a circuit breaker. This transformer may have been produced in 1960. Confirmation of this is requested.