When assisting a disabled train in DCS territory, what must the helping train be issued?

When assisting a disabled train in DCS (Discrete Control System) territory, the helping train must be issued Form D line 9. This form is specifically used to authorize movements in DCS territory, ensuring that the movement is controlled and that the necessary safety protocols are followed. Form D line 9 effectively communicates permission for the assisting train to enter an area where a disabled train is located and outlines the conditions under which this assistance is to occur.

Utilizing Form D line 9 helps maintain safety and organization on the tracks, particularly in scenarios where non-standard operations are taking place due to a disabled train. The form ensures that all involved parties are aware of the situation and can act accordingly to mitigate risks.

Other options do not meet the requirement for proper authorization under these circumstances. For instance, Form D line 0 is not applicable in this situation, as it relates to a different aspect of train operations. Similarly, Form D line 1 pertains to granting permission for a train to occupy a segment of track but does not specifically address the scenario of assisting a disabled train. Issuing no forms would lack the necessary safety measures required for proper operation in DCS territory.