What characteristic defines "yard track" in railway operations?

Yard track is typically defined by its use and the operational speed limits associated with it. The characteristic that distinguishes yard tracks is that they are designed for movements operating at Restricted Speed, typically not exceeding 10 MPH. This restriction is crucial because yard tracks are often busy and cluttered with various activities such as switching, assembling trains, and storing rail cars. The slower speed enhances safety, allowing for vigilant observation of activities and quick responses to any potential hazards that may arise in a busy rail yard environment.

In this context, while other options reference important operational aspects, they do not capture the fundamental characteristic defining the nature of yard tracks in terms of speed and safety requirements.