Rail vehicle wheel flanges: On which side of the rolling stock wheel are the flanges provided to ensure guidance on the rail?

Introduction / Context:
Wheel flanges are critical to guiding railway vehicles along track, keeping the wheels on the rails at curves, switches, and crossings. Their placement determines how they interact with rails and check rails.

Given Data / Assumptions:

• Standard solid-axle, coned-tread wheelsets used on conventional railways.
• Normal right-way-up track with standard rail head profile.

Concept / Approach:
Each wheel has a flange on its inner side (gauge side). The flange provides lateral restraint against the rail gauge face, while the coned tread assists in self-centering and steering.

Step-by-Step Solution:
Identify the gauge face of the rail (inner side).Recall that flange must contact gauge face for guidance.Hence, flange location is on the inner side of each wheel.

Verification / Alternative check:
Track diagrams show check rails placed against the inner side to control flange path at crossings, consistent with inner-side flanges.

Why Other Options Are Wrong:

• Outer side/both sides: Not used; would cause clearance and interference issues.
• Neither side: Contradicts fundamental wheel–rail guidance.
• On the crown only: No such practice; the crown is tread region, not a flange.

Common Pitfalls:
Confusing “outer” with “field” side; overlooking check-rail function which acts with inner flanges.

Final Answer:
inner side