Under what circumstances can an assisting train make an opposing movement without receiving Form D line 9?

The correct answer focuses on specific operational protocols that govern train movements. In this case, assisting trains are permitted to make opposing movements without receiving Form D line 9 under certain conditions aimed at ensuring safety and operational efficiency.

When an assisting train is stopped within a quarter mile of an interlocking or if the engineer of the disabled train is operating it, the movement is considered safe to proceed without additional authorization. This protocol recognizes that the engineer of the disabled train is privy to the situation and understands the hazards involved, which allows for an informed decision to be made regarding the movement.

In contrast, the other options do not align with established safety protocols or operational rules. Proximity to a passenger station does not inherently create a safe environment for opposing movements, and communication with the disabled train crew, while potentially beneficial, does not substitute for formal orders like Form D line 9. Lastly, simply waiting for ten minutes does not provide sufficient assurance that conditions have stabilized or that the opposing movement is safe. Thus, understanding the specifics of operational rules, particularly regarding interlocking locations and direct engineer involvement, is vital for train safety and procedural adherence.