In NORAC 100, what best describes a block?

• A. A continuous stretch of track without any signals.
• B. A defined segment of track bounded by block signals.
• C. A defined segment of track bounded by block signals where train movements are controlled within that segment.
• D. The area immediately adjacent to the switch.

Answer: (C)

Block in NORAC 100 is a defined segment of track bounded by block signals, with train movements inside the segment controlled by those signals. This setup ensures safe train separation by making sure only one train occupies the block at a time and that authority to enter or proceed is indicated by the signal aspect. The description that includes both the boundaries set by block signals and the control of movement within the segment best captures how blocks function, which is why it’s the right choice. Descriptions that omit the control inside the segment miss how a block protects against conflicting movements, and calling a block simply a stretch without signals ignores the boundary signals that define it. The area next to a switch is not what defines a block, since a block can include switches and is defined by its end signals and the control within it.