What should be the normal position of the operating brake valve when running over the road?

The normal position of the operating brake valve when a train is running over the road should be in the "Release" position. This allows the brake system to maintain a state where the brakes are not applied, enabling the train to travel freely and efficiently. In this position, air is allowed to flow to the brake cylinders, which reduces the pressure and ensures that the brakes are disengaged.

Having the brake valve in the release position is essential for safe and effective train operation, as it prevents unnecessary wear on the braking components and helps maintain the proper speed and handling of the train. When the brakes are released, it also allows the engineer to respond to any changes in the train's operating conditions, such as acceleration or deceleration, without the hindrance of engaged brakes.

In contrast, having the valve set to "On" would mean the brakes are actively engaged, which is not appropriate during regular travel. The "Off" position would imply that the brake system is disabled, which could be dangerous. The "Emergency" position is only used in critical situations when an immediate stop is required, thus it would not be suitable for everyday operations. Overall, keeping the operating brake valve in the release position facilitates smooth and safe train operation.