How must the Third Rail be considered?

• A. Always de-energized.
• B. Energized (Live), except when de-energized, tested de-energized, third rail warning device applied, and protection is provided by a qualified Class "A" third rail Employee.
• C. Isolated by a switch.
• D. Energized (Live) with no warnings.

Answer: (B)

The third rail is part of the traction power system and presents a high electrical hazard, so it must be treated as energized in normal operation. You only regard it as de-energized when you have confirmed isolation and have tested to verify there is no voltage present. When work is being done, a third rail warning device must be in place to alert others, and protection must be provided by a qualified Class a third rail employee. This combination balances safety with the need to perform maintenance, because it prevents accidental contact with live power while permitting authorized work under controlled conditions. The other approaches fail because they either assume it’s always off, rely on a simple switch without the full protective process, or allow work near a live third rail with no warnings, all of which would be unsafe.