History of Indian gauge selection — as Consulting Engineer to the Government of India, W. Simms recommended which gauge for Indian Railways?

Introduction / Context:
Gauge selection has shaped the evolution of Indian Railways. Early deliberations weighed cost, stability, and terrain. W. Simms' recommendation set the stage for the broad gauge that still dominates trunk routes in India.

Given Data / Assumptions:

• Timeframe: formative years of Indian Railway construction.
• Objective: a gauge suited to Indian traffic and conditions, balancing stability and economy.
• Multiple gauges were in use worldwide; a compromise was sought.

Concept / Approach:

The 1.676 m (5 ft 6 in) gauge was recommended as a compromise gauge offering improved stability and capacity over standard gauge, yet not as expensive as even wider proposals. This decision influenced route standards, structures, and rolling stock dimensions for generations.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Historical records of early Indian Railways policy and correspondence attribute the advocacy of 1.676 m to senior engineers and committees, including W. Simms’ role.

Why Other Options Are Wrong:

1.435 m is the European/English standard but was not adopted for most Indian trunk lines. 1.000 m is metre gauge used on many branch lines later. 1.800 m and 1.520 m do not reflect India’s adopted mainstream gauge.

Common Pitfalls (misconceptions, mistakes):

Assuming global standard gauge was universally adopted; confusing metre gauge expansion with the initial trunk-line policy.

Final Answer:

1.676 m as a compromise gauge