Which speed category ensures stopping within one half the range of vision and has limits of 20 mph outside interlockings and 15 mph inside interlockings?

Which speed category ensures stopping within one half the range of vision and has limits of 20 mph outside interlockings and 15 mph inside interlockings?

• A. Limited speed
• B. Medium speed
• C. Slow speed
• D. Restricting speed

Answer: (D)

Restricting speed is the category that requires you to be able to stop within half the range of vision. That safety rule is paired with the specific limits: 20 mph outside interlockings and 15 mph inside interlockings. The reason this fits is that interlockings are areas with complex track geometry and moving pieces, where quicker, predictable stopping is essential. Inside interlockings, the environment is even tighter and more hazardous, so the lower limit applies. Outside interlockings, you still must be able to stop quickly, but the limit is a bit higher due to comparatively fewer immediate conflicts. The other speed categories don’t specify this half-vision stopping criterion or these exact mph thresholds, so they don’t match the described requirement.

Restricting speed is the category that requires you to be able to stop within half the range of vision. That safety rule is paired with the specific limits: 20 mph outside interlockings and 15 mph inside interlockings. The reason this fits is that interlockings are areas with complex track geometry and moving pieces, where quicker, predictable stopping is essential. Inside interlockings, the environment is even tighter and more hazardous, so the lower limit applies. Outside interlockings, you still must be able to stop quickly, but the limit is a bit higher due to comparatively fewer immediate conflicts. The other speed categories don’t specify this half-vision stopping criterion or these exact mph thresholds, so they don’t match the described requirement.