Crossing components: Where are wing rails provided in a turnout/crossing assembly?

Introduction / Context:
Wing rails are special rails that flank the nose of a crossing (the V) to guide wheel flanges safely across the gap at the crossing. Correct identification of their location is fundamental to turnout anatomy.

Given Data / Assumptions:

• A standard turnout consists of switch (tongue and stock rails) and crossing (nose, wing rails, check rails).

Concept / Approach:
At the crossing, the wheel must bridge a gap. Wing rails provide the guiding surfaces and maintain the correct flangeway, working with check rails on the opposite rail to ensure smooth passage and prevent flange picking of the nose.

Step-by-Step Solution:
Identify the crossing portion (V-crossing).Wing rails are positioned adjacent to and diverging from the nose.Hence, the correct location is at the crossing.

Verification / Alternative check:
Standard turnout drawings show wing rails integral to the crossing assembly, clearly labeled and dimensioned.

Why Other Options Are Wrong:

• Switch/tongue area: has tongue and stock rails, not wing rails.
• Check rails are separate components used opposite the crossing to control flange path, not in place of wing rails.

Common Pitfalls:

• Mislabeling check rails as wing rails; both guide flanges but are in different positions and serve complementary roles.

Final Answer:
In crossing.