What is Ballast?

What is Ballast?

• A. A structure at the end of track placed to prevent rail vehicles from running off the track.
• B. Selected material placed onto the roadbed for the purpose of holding the track in proper alignment and providing proper drainage.
• C. A section of track of defined limits, the use of which is controlled by signals or other means.
• D. Information issued in writing by the Rail Operations Manager which may be a temporary or permanent change in the rules or procedures.

Answer: (B)

Ballast is the material placed onto the roadbed to hold the track in proper alignment and provide drainage. This crushed stone or similar aggregate sits under and around the ties to distribute loads from trains to the ground, keep the rails at the correct gauge, and allow water to drain away from the subgrade, preventing instability and frost damage. Regular maintenance, like tamping, relevels and repositions the ballast to maintain alignment. The other options describe a safety device at the end of track, a defined track section controlled by signals, and a written procedural notice—none of which is ballast.

Ballast is the material placed onto the roadbed to hold the track in proper alignment and provide drainage. This crushed stone or similar aggregate sits under and around the ties to distribute loads from trains to the ground, keep the rails at the correct gauge, and allow water to drain away from the subgrade, preventing instability and frost damage. Regular maintenance, like tamping, relevels and repositions the ballast to maintain alignment. The other options describe a safety device at the end of track, a defined track section controlled by signals, and a written procedural notice—none of which is ballast.