What is required before a train can change direction at a spring switch?

For a train to change direction at a spring switch, it is essential to "line the switch by hand." This is because a spring switch is designed to automatically revert to its default position after a train passes through. However, for it to safely divert a train in a specific direction, a crew member must manually adjust the switch to the desired position before the train arrives. This action ensures that the switch is correctly set to allow the train to move onto the correct track without any risk of derailment or accidents. Properly aligning the switch is crucial for maintaining safe and efficient operations during switching maneuvers.

Ensuring all signals are green, notifying the dispatcher, and checking the locomotive's speed are important safety procedures in rail operations, but none of these actions directly facilitate the physical change of direction at the spring switch itself.