The movement of trains on a main track in one direction, as specified by special instruction.

• A. Main Track
• B. Secondary Track
• C. Industry Track
• D. Current of Traffic

Answer: (C)

In railroad operation, the way trains are allowed to move on a main track in a single direction is described by the current of traffic. This term communicates which direction trains are authorized to run on that main-line segment under the current instructions or timetable. It’s all about the directional flow of movement on the main line as established by control signals and special instructions. An industry track, by contrast, is a track used to move cars to and from industry customers and does not define the direction of main-line traffic. So the phrase about one-way movement on the main track is tied to the current of traffic, even though industry tracks are a separate category used for serving facilities.