What are the two positions of the brake valve most commonly used when graduating off the brakes?

The two positions of the brake valve most commonly used when graduating off the brakes are indeed the release and electric holding positions.

When a train operator graduates off the brakes, they're transitioning from a braking situation to a more controlled state, which often involves releasing the brakes fully. The release position allows for the brakes to be released completely, facilitating a seamless continuation of motion or a reduction in stopping power. The electric holding position is particularly important when operators need to maintain a holding force without applying full brake pressure, providing control in various situations, such as during station stops or when standing on an incline.

This method of using both the release and electric holding positions helps ensure safe and controlled operation of the train, allowing the operator to manage speed effectively and maintain safety standards. The other positions mentioned in the other choices serve different purposes and may not specifically address the incremental approach to controlling braking while moving.