When Phase Break (PB) indicator is lit, a section of the PB is de-energized, all electric equipment approaching must?

• A. Place throttle OFF and open the MCB, keeping it in that position until the PB is passed.
• B. Do nothing until the PB sign is reached.
• C. Lower pantographs on all locomotives prior to PB entry.
• D. Stop immediately and reverse direction.

Answer: (A)

Phase Break means the trailing section of the traction power is de-energized ahead of you, so the safe action is to cut power and isolate the circuit as you approach. Place the throttle in OFF and open the main circuit breaker, and keep it open until you have passed the Phase Break. This prevents any electrical energy from feeding into the dead section, avoiding backfeed, arcing, or equipment damage as you move through the break.

Continuing with power or waiting for the PB to vanish would risk energizing the de-energized section. Lowering pantographs isn’t a reliable way to guarantee isolation of the dead segment, and stopping and reversing isn’t the prescribed method for handling a Phase Break.