Which of the following is directly classified as a freight train?

A freight train is specifically designed and utilized for transporting goods and materials rather than passengers. Therefore, it encompasses any train that is not tasked with passenger services. This definition aligns with the concept of freight transport, which focuses on the movement of cargo rather than people.

The other options refer to either trains that transport passengers or specific designations that do not inherently relate to freight classification. A passenger train, regardless of its stopping schedule, is still primarily focused on human transportation, which is distinctly different from the function of a freight train. The designation "Extra" is not an exclusive characteristic of freight trains; it could refer to any train operating outside of the regular schedule. Thus, the choice that accurately identifies a freight train is the one that emphasizes its role in goods transportation without reference to passenger services.