What term refers to railroad cars, engines, or track cars collectively?

The term that refers to railroad cars, engines, or track cars collectively is "Equipment." In the context of railroading, "equipment" is a broad term that encompasses all rolling stock and locomotives used in the operation of trains. This includes not just freight and passenger cars, but also specialized vehicles such as maintenance-of-way cars, which are used for track maintenance and repair. Recognizing equipment as a collective term emphasizes its integral role in rail operations, ensuring that trains can function effectively and safely.

The other terms mentioned do not encompass the entirety of railroad rolling stock and vehicles. "Absolute Block" indicates a specific signaling and train control system used to prevent collisions, while "Extra Train" pertains to a train that operates outside of the normal schedule or service. "Freight Train" specifically refers to a train composed solely of freight cars, which excludes passenger cars or other types of equipment. Thus, "Equipment" is the most inclusive and accurate term for referring to all the various car types and locomotives used in railroad operations.