In Track Warrant Control, the boundary of authority is defined by the last named point plus the first switch at that point. So when the last named point is a station, the train’s authority extends to and includes the first switch located at that point. This switch marks the actual boundary between blocks, so movement up to and through that switch is covered, but anything beyond that switch requires a new or additional warrant. Other interpretations—such as stopping at the next station, the end of track, or a mile marker—don’t reflect how warrants delineate limits with the boundary defined by the switch at the last named point.

The main idea is that a track warrant is valid only while the track section is available and safe to use. If weather or other conditions make that track inaccessible, the warrant must be canceled so trains don’t enter a section that’s not usable. A storm closing the track is a direct and straightforward reason: it immediately makes the track unsafe or unusable, so canceling the warrant prevents any movement into that area until service can safely resume. In practice, officials will revoke the authority when the track is shut and issue new instructions once it’s reopened.

When there are conflicting movements under warrants, one movement must be controlled by the more restrictive authority and the dispatcher must be contacted to resolve the conflict. This safety rule ensures that the movement with tighter limits in time, location, or conditions takes precedence, reducing the chance of collisions or unsafe occupancy. The dispatcher can issue a revised warrant or give concrete instructions to safely clear the conflict and continue operations. Why the other ideas don’t fit: ignoring the conflict creates a clear safety risk; stopping until tomorrow is impractical and unsafe; following the oldest warrant ignores current safety constraints and the actual restrictions in place.

Relaying a track warrant is permitted because the authority to move on a defined track segment must be available to the crew that needs it, even if the original recipient isn’t present. When someone holding the warrant can’t be reached, another qualified employee can pass the warrant’s details to the appropriate crew, ensuring continuous operation without sacrificing safety. The relayer must convey all essential content—who issued the warrant, the exact segment and limits, any conditions, and the expiration time—and the receiving person must acknowledge and log the transfer, with the dispatcher kept informed so the authority chain stays current. This keeps trains moving efficiently while maintaining clear, auditable control of movements. The other options don’t fit because warrants are not restricted to a no-relay rule, nor do they require dispatcher permission for every relay, and bulletins are a separate type of instruction from warrants.