How must Multiple Electric engines coupled run with double Pantograph order?

How must Multiple Electric engines coupled run with double Pantograph order?

• A. With both Pantographs up on the leading unit and rear Pantograph up on trailing unit except through Phase Break (PB) (when Lit). Drop all Pantographs prior to entering PB and DS.
• B. All Pantographs up on both units at all times.
• C. Only the trailing unit's pantographs up.
• D. Pantographs down on all units during phase breaks.

Answer: (D)

Phase breaks are changes in the traction power feed where the overhead wire sections aren’t energized or are on different feeders/phases. When multiple electric locomotives are coupled, keeping pantographs down during these breaks prevents any contact with the wire while the power status is uncertain. This avoids arcing, backfeeding between sections, and potential damage to the pantographs or the catenary system. Once the system is re-energized beyond the break, the pantographs can be raised again to resume current collection. Keeping pantographs up on all units at a phase break can create dangerous arcing or cross-feed between different power sections. Having only the trailing unit’s pantographs up doesn’t reliably isolate the lead unit, which can still interact with the overhead in a way that’s unsafe during the transition. So the safest and correct practice is to have pantographs down on all units during phase breaks.

Phase breaks are changes in the traction power feed where the overhead wire sections aren’t energized or are on different feeders/phases. When multiple electric locomotives are coupled, keeping pantographs down during these breaks prevents any contact with the wire while the power status is uncertain. This avoids arcing, backfeeding between sections, and potential damage to the pantographs or the catenary system. Once the system is re-energized beyond the break, the pantographs can be raised again to resume current collection.

Keeping pantographs up on all units at a phase break can create dangerous arcing or cross-feed between different power sections. Having only the trailing unit’s pantographs up doesn’t reliably isolate the lead unit, which can still interact with the overhead in a way that’s unsafe during the transition. So the safest and correct practice is to have pantographs down on all units during phase breaks.