Final answer:
The term 'slippered a contact shoe' likely refers to disengaging the contact shoe from the power source in rail transport, though it is not standard terminology.
Step-by-step explanation:
When referring to a train operator slippering a contact shoe, it typically means that the shoe, which is a part of the train's pickup system for electricity, has been temporarily or permanently removed or has lost contact with the overhead wire or third rail. This could happen for various reasons such as maintenance, damage to the shoe, or due to an operational error. The term 'slippered' is not a commonly used term in the railway industry, so context is important for a precise definition. However, considering standard railway terminology, an assumption can be made that it refers to the act of disengaging the shoe from its functioning position.