Final answer:
Without specific information on the ME-23 brake valve, we cannot provide an accurate answer to the question regarding its normal position during train operation. The position of brake valves depends on the particular design and function as outlined by the manufacturer or operator training materials.
Step-by-step explanation:
The question about the normal position of the ME-23 brake valve while a train is running is generally related to the field of Engineering, specifically to railway engineering and train operation systems. The context of the question suggests that it may be testing knowledge of train brake systems, rather than providing information about specific models of brake valves.
The correct answer would typically depend on the specific design and operation of the ME-23 brake valve. However, since the details of the ME-23 brake valve are not provided, and only multiple-choice options are available without any reference to them being part of the original question, no accurate and factually supported answer can be given to this query.
Train operators and engineers commonly use brake valves to control the air pressure in the brake system to apply or release the brakes. The normal running position is often designed to maintain a balance that will ensure the brakes are not applied yet ready to be activated when needed. The specific position for the ME-23 brake valve, be it equilibrium, extreme, or another position, would be found in the manufacturer's equipment manual or the operator's training materials.