For railway alignment in rugged terrain, which options may be considered depending on economics and terrain—detour around the hill, open cut through the hill, or tunnelling—and which overall statement best reflects practice?

Difficulty: Easy

A detour around the hill is preferred
An open cut through the hill is preferred
Tunnelling through the hill is preferred
All the above.
None of the above

Correct Answer: All the above.

Explanation:

Introduction / Context:
Railway route selection weighs cost, grade constraints, curvature, land acquisition, and environmental impacts. Depending on site conditions, engineers may choose to detour, cut, or tunnel. This question checks recognition that all three are legitimate alternatives evaluated during feasibility and detailed design, with the final choice being context-dependent.

Given Data / Assumptions:

Terrain: hill or ridge obstructing the desired rail alignment.
Feasible solutions: detour, open cut, or tunnel.
Decision basis: economics, operations, safety, and environmental factors.

Concept / Approach:
A detour can avoid heavy works but increases distance and operational energy. An open cut shortens the route but demands large excavation and slope stabilization. A tunnel provides the straightest line but requires specialized construction and ventilation. Since any of these can be “preferred” in the right circumstances, the comprehensive answer acknowledges all three options as valid choices considered by railway planners.

Step-by-Step Solution:

Quantify costs for each alternative including earthworks, structures, and track geometry.Check operational impacts: grades, curvature, travel time, and energy consumption.Assess environmental and land impacts, then choose the least-cost, most reliable solution.

Verification / Alternative check:

Case histories show all three approaches used successfully; the “best” option varies project to project.

Why Other Options Are Wrong:

Each single alternative may be optimal sometimes, but none is universally superior. Hence only “All the above” captures the real design choice set.

Common Pitfalls:

Assuming tunnels are always costlier; deep open cuts can exceed tunnel costs when stabilization is extensive.

Final Answer:

All the above.

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For railway alignment in rugged terrain, which options may be considered depending on economics and terrain—detour around the hill, open cut through the hill, or tunnelling—and which overall statement best reflects practice?

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