What is the primary difference between Rule 251 and Rule 261 regarding train operations?

The primary difference between Rule 251 and Rule 261 lies in their operational applications concerning train movements. Rule 261 covers scenarios involving both opposing and following movements. This means that trains operating under Rule 261 have more versatility in their approach to signal indications and allowable movements.

Under Rule 261, trains can proceed in situations where standard signals apply, allowing them to manage the flow of traffic even when there is a potential for trains to face each other or to follow closely behind. This is particularly important in busy corridors where the efficient management of train schedules is essential.

In contrast, when considering the other options, Rule 251 primarily focuses on allowing opposing trains to operate under clearly defined conditions, emphasizing exclusive track use to prevent conflicts. This sets a stricter boundary on train movements as compared to Rule 261, which accommodates a wider range of operational possibilities and encourages more flexible scheduling and routing while maintaining safety.

Therefore, understanding this distinction helps to clarify how the rules apply to real-world scenarios, particularly in managing train traffic on shared tracks.