Indian B.G. vehicle constraints — the maximum wheelbase commonly permitted on Broad Gauge tracks is approximately:

Introduction / Context:
Vehicle dynamics on curves and turnouts are sensitive to the rigid wheelbase (distance between extreme coupled axles). Railway standards limit maximum wheelbase for safe negotiation of curvature without excessive flange wear or rail forces. This question recalls the typical Indian B.G. limit used in design checks and vehicle clearance rules.

Given Data / Assumptions:

• Standard Indian Broad Gauge (1676 mm).
• Conventional rolling stock (non-articulated, rigid frame).
• Historic standard limits used for layout and speed checks.

Concept / Approach:

A commonly cited maximum rigid wheelbase for Indian B.G. stock is about 6.096 m (20 ft). This value is used to verify curve radii, check rail clearances, and turnout geometry so that vehicles can traverse without binding or excessive flange contact.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Check permanent way manuals/vehicle standards; the 20 ft wheelbase limit historically appears in design tables for curves/turnouts.

Why Other Options Are Wrong:

4.096 m and 5.096 m are below typical maxima; 7.096 m exceeds usual constraints for general stock, risking poor curving performance.

Common Pitfalls (misconceptions, mistakes):

Confusing bogie wheelbase with rigid wheelbase; mixing BG values with MG/NG constraints.

Final Answer:

6.096 m