Turnout and crossings terminology: Which arrangement of rails allows a train both to cross another track and to be diverted to that other track from the same location?
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Adiamond crossing
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Bdiamond crossing with single slip
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Cdiamond crossing with double slip
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Dcross over
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Escissors crossover
Answer
Correct Answer: diamond crossing with double slip
Explanation
Introduction / Context:Complex track layouts enable crossing and routing flexibility in constrained yards and station throats. Understanding the capability of each arrangement is essential for operations and design.
Given Data / Assumptions:
- We compare diamond crossings, slips, and crossovers.
- The desired function is both crossing and diverging to the intersecting track at one location.
Concept / Approach:A plain diamond permits only crossing. Adding slips inserts switch diamonds that enable a route from one track to the other. A single slip allows diversion in one of the two diagonal directions, whereas a double slip provides both directions, maximizing flexibility within the diamond footprint.
Step-by-Step Solution:Identify plain diamond: crossing only.Add one slip (single slip): allows crossing and one-direction turnout.Add two slips (double slip): allows crossing and diversion to the other track in both directions.
Verification / Alternative check:Track schematics show the double slip has four switch tongues integrated into the diamond, offering full flexibility.
Why Other Options Are Wrong:
- Diamond crossing: no turnout function.
- Single slip: only one-direction diversion.
- Cross over: two separate turnouts allowing a train to transfer between parallel tracks, not at the intersection of two crossing tracks.
- Scissors crossover: compact pair of crossovers between parallel tracks, not a crossing of intersecting tracks.
Common Pitfalls:Confusing crossovers between parallel tracks with slip arrangements inside a crossing; assuming any diamond allows turnouts without slips.
Final Answer:diamond crossing with double slip