What does a Form D authorizing TC movement permit in terms of distance to an interlocking or CP?

A Form D authorizing TC (Track Car) movement specifically permits movement only to the home signal of the final interlocking. This is significant because it establishes a clear limitation on the extent of the authorization, providing clarity and safety for operations. By designating the home signal of the final interlocking as the endpoint, it ensures that the train or track car does not proceed beyond a controlled and predetermined point, maintaining signal integrity and preventing conflicts with other movements.

The home signal serves as a key reference point in railway operations, as it indicates the limits beyond which further control measures are needed. This practice aligns with safety protocols and operational standards intended to safeguard against potential accidents and to manage train movements effectively.

The other options suggest more extensive permissions that could lead to operational ambiguities or safety risks. For instance, suggesting movement to the next Control Point (CP) could allow for unintended interaction with other trains or movements not governed by the same track authority. Thus, limiting movement strictly to the home signal of the final interlocking simplifies the operational constraints and enhances safety.