What device is mounted to the running rail to keep wheels in line at switches?

• A. Guard Rail
• B. Restraining Rail
• C. Hi-Rail Equipment
• D. Flag

Answer: (A)

Guard rail is the device that keeps wheels centered and aligned as they pass through a switch. It’s a secondary rail mounted along the inside of the turnout that your wheel flange rides against or contacts just enough to guide the wheel onto the correct path. By doing this, it prevents the wheel from wandering or climbing over the running rail at the switch, reducing derailment risk and helping the train follow the intended route through the turnout. The other options don’t serve this wheel-guiding role: a flag is for signaling, hi-rail equipment is maintenance gear, and while some might use terms like restraining rail, the standard term used in practice and on exams is guard rail for this purpose.