Identify the correct description of steel sleepers used on Indian Railways.

Introduction / Context:
Sleepers provide support and gauge restraint for rails. Steel sleepers commonly used in India are pressed trough sections designed to give stiffness, fastening support, and ballast interlock.

Given Data / Assumptions:

• Standard Indian steel sleeper design.
• Thickness ~6 mm is typical for pressed trough sections.

Concept / Approach:

Pressed trough steel sleepers have ends bent up to improve strength, provide bearing area at rail seats, and contain ballast. The shape increases section modulus while keeping weight manageable, and accommodates clips or fastenings.

Step-by-Step Solution:

Verification / Alternative check:

Manufacturers’ drawings show characteristic trough with upturned ends and rail seats prepared for fastenings.

Why Other Options Are Wrong:

Solid rectangular sections are uneconomical; ends bent down is not the standard; pipe-type and cast blocks are not the typical steel sleeper solution.

Common Pitfalls:

Confusing steel sleepers with cast-iron or PSC sleepers; misremembering the direction of end bends.

Final Answer:

6 mm thick pressed steel trough with ends bent up