Railway permanent way design — for providing a crossover between two parallel tracks, which set of components is required in standard practice?

Introduction / Context:
A crossover is a pair of turnouts that connects two parallel railway tracks, allowing movements from one line to the other. Understanding the necessary components—switches (points), crossings, and check rails—is fundamental in railway track design and yard layout planning.

Given Data / Assumptions:

• The crossover connects two parallel tracks of the same gauge.
• Standard right-hand and left-hand turnouts are used to form the crossover.
• Each acute (V) crossing requires appropriate check rails to control wheel flange guidance.

Concept / Approach:

A basic crossover comprises two turnouts (hence two switch points) facing opposite directions. The diverging tracks intersect the parallel track with two acute angle (V) crossings—one at each turnout. At every acute crossing, check rails are provided on the opposite rail to prevent flange climb and to steer the wheelset correctly through the crossing nose. Typically, two check rails are associated with each acute crossing, so a standard two-crossing crossover requires four check rails in total.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Check a standard track layout diagram of a simple crossover; counting the V-crossings and associated check rails will confirm the 2 acute crossings and 4 check rails, plus the two switch point assemblies.

Why Other Options Are Wrong:

Options with two or six check rails do not match the standard arrangement for two acute crossings (which need four). Options listing obtuse crossings belong to more complex layouts (e.g., scissors, diamonds) rather than a simple crossover.

Common Pitfalls (misconceptions, mistakes):

Confusing a simple crossover with a scissors crossover; forgetting that each acute crossing needs a pair of check rails for guidance; assuming obtuse crossings are required in a basic crossover.

Final Answer:

two switch points, two acute angle crossings and four check rails