Which of the following is NOT a condition under which railroad operating employees can use electronic devices?

The correct choice highlights a critical safety protocol in railroad operations. Railroad operating employees are prohibited from using electronic devices while on the ground within 4 feet of any track due to the heightened risk of accidents in these zones. This rule is put in place to ensure that employees remain fully focused on their surroundings, as being near tracks increases the likelihood of encountering moving trains and other hazards.

Using electronic devices in such close proximity to tracks could distract employees from noticing any oncoming trains or other safety issues, thereby jeopardizing their safety and the safety of others. This requirement is part of a broader safety strategy to minimize distraction and ensure vigilant awareness in potentially dangerous locations.

The other scenarios presented, while under regulation, allow for the use of electronic devices under specific conditions: when safety briefings have taken place, during certain preparatory tasks, or when conducting necessary railroad business in a controlled environment. These conditions are recognized as safer contexts where employees can manage distractions properly while still adhering to operational protocols.