The distance limitation for movement beyond the home signal is measured in what units?

The distance limitation for movement beyond the home signal is measured in what units?

• A. One signal length
• B. One train length
• C. One mile
• D. The next interlocking

Answer: (B)

Movement beyond a home signal is limited by a distance equal to one train length. In practice, this means the train may advance only as far beyond the signal as the length of the train itself. Using train length as the unit keeps the protection consistent for trains of different sizes and ensures the entire train remains within the block’s safety envelope, giving the crew time to react to the next signal or any obstruction. It aligns with how the signaling and track circuits protect entrances to blocks, so going farther would undermine that protection. Units like a signal length, miles, or reaching the next interlocking don’t fit the safety and occupancy framework NORAC uses, which is why one train length is the correct measure.

Movement beyond a home signal is limited by a distance equal to one train length. In practice, this means the train may advance only as far beyond the signal as the length of the train itself. Using train length as the unit keeps the protection consistent for trains of different sizes and ensures the entire train remains within the block’s safety envelope, giving the crew time to react to the next signal or any obstruction. It aligns with how the signaling and track circuits protect entrances to blocks, so going farther would undermine that protection. Units like a signal length, miles, or reaching the next interlocking don’t fit the safety and occupancy framework NORAC uses, which is why one train length is the correct measure.