Application of bull-headed rails in permanent-way Bull-headed (BH) rails carried in chairs are generally preferred in which of the following track locations due to fitting compatibility and traditional practice?

Introduction / Context:
Bull-headed rails, historically mounted in cast-iron chairs with keys, have been widely used in complex trackwork like switches and crossings. Their geometry and legacy fittings made them compatible with traditional point and crossing assemblies.

Given Data / Assumptions:

• Context is conventional track with legacy components.
• Focus on where BH rails are generally provided, not modern flat-bottom dominance.

Concept / Approach:
In pointwork, precise rail seating, adjustability, and compatibility with chairs are critical. BH rails historically satisfied these needs, especially before widespread adoption of flat-bottom rails with baseplates and elastic fastenings in complex layouts.

Step-by-Step Solution:
Identify locations with highest fitting complexity: switches and crossings.Recognize traditional use of chairs and keys with BH rails.Hence, BH rails were commonly provided at points and crossings.

Verification / Alternative check:
Historic drawing archives and maintenance manuals list BH in many legacy point and crossing installations, though modern renewals may prefer flat-bottom rails with appropriate components.

Why Other Options Are Wrong:
Straight tangents/curves: BH could be used, but they were not specifically “generally provided” there over modern alternatives.Metre gauge: Gauge does not mandate BH; application depends on fittings.

Common Pitfalls:

• Confusing historical prevalence with current standard practice; many railways now standardize flat-bottom sections even in pointwork.

Final Answer:
points and crossing