On Broad Gauge (B.G.) tracks of Indian Railways, the standard grade compensation for curvature is taken as

Introduction / Context:
On curves, additional resistance acts on trains due to flange and alignment effects. To maintain equivalent tractive effort, railways reduce the ruling gradient on curves—a practice called grade compensation. Values differ by gauge and administration; Indian standards adopt conventional fixed percentages.

Given Data / Assumptions:

• Gauge: Broad Gauge (B.G.).
• Typical Indian Railways practice for main-line design.
• Compensation is a fixed percentage per degree of curve applied to the ruling gradient.

Concept / Approach:

Grade compensation offsets curve resistance so that locomotives face similar total resistance on curves as on straight reaches. For B.G., a widely used standard figure is 0.04% per degree of curve, applied to the gradient, limited so as not to over-flatten grades excessively.

Step-by-Step Solution:

Verification / Alternative check:

Design manuals and standard textbooks list 0.04% for B.G., with different values for other gauges (e.g., M.G. often 0.03%).

Why Other Options Are Wrong:

Other values do not reflect the standard B.G. practice; 0.05% or 0.06% would overcompensate, while 0.02–0.03% undercompensate for B.G.

Common Pitfalls:

Confusing grade compensation per degree with superelevation; applying compensation without checking maximum limits specified for particular routes.

Final Answer:

0.04%