Any on-track vehicle, except a wreck train, that is used to house railroad or contract employees.

• A. Extra Train
• B. Camp Car
• C. Passenger Train
• D. Track Car Extra

Answer: (B)

The main idea is identifying the on-track vehicle that's purpose-built to house workers. A camp car is exactly that: a on-track unit equipped with living quarters to accommodate railroad or contract employees while they work on maintenance or construction projects. It stays with the work crew on the right-of-way and provides bunks, meals, and facilities as needed, rather than transporting passengers or carrying out other functions.

The other options don’t fit the housing purpose. An extra train is used to handle additional passenger or freight service, not to house crews. A passenger train is for transporting riders. A track car is typically a small maintenance vehicle for inspections or light work, not a living space. So the term that best matches the description is camp car.