Final answer:
The distance at which a signal is placed for a train to resume speed after slowing down for track work depends on safety and railway regulations. Specific distance is not provided without additional information.
Step-by-step explanation:
When a train operator is signaled to slow down due to men working on the tracks, they should expect to see a signal beyond the work area indicating that it is safe to resume normal speed.
This signal is typically placed at a distance that allows the train to safely accelerate back to its regular speed without endangering the workers or the train's passengers. In real-world practice, the exact distance may vary based on various factors, including the train's speed, stopping distance, visibility, and railway regulations. However, to provide a specific answer, more information is needed, such as railway standards or additional context.