The limit of authority on a hand-operated switch is located at which point?

• A. The fouling point.
• B. The switch handle.
• C. The turnout midpoint.
• D. The operator's station.

Answer: (A)

The key idea here is where authority to set a switch ends. For a hand-operated (hand-thrown) switch, the limit of authority is placed at the fouling point. The fouling point is the location on the track where a train’s wheel first interacts with the switch points; it’s the boundary beyond which switch movement can directly affect the route a train would take. Placing the limit there prevents the operator from altering the switch in a way that could misalign the track and create an unsafe condition without proper authority.

The switch handle is simply the control device, not the boundary of authority. The turnout midpoint isn’t a safety boundary, and the operator’s station refers to where the operator stands or sits, not the LOA boundary in the field.