CST-9 sleeper components — which of the following correctly describes the elements that make up a standard CST-9 cast-iron sleeper assembly?

Introduction / Context:
CST-9 sleepers (cast-iron pot sleepers) were widely used on Indian railways. Knowing their parts helps in inspection, maintenance, and exam questions focused on legacy sleeper types and fastenings.

Given Data / Assumptions:

• CST-9 consists of two separate cast-iron “pots” connected by a tie arrangement.
• Central seat and keying arrangements secure the rail foot.
• Standard fastening set includes tie bar and cotters.

Concept / Approach:

A typical CST-9 has two cast-iron pot plates placed on either side of the rail seat. A central plate with key box accommodates a key to hold the rail. The two pots are tied together by a steel tie bar, commonly secured with four cotters. The key arrangement ensures gauge side restraint of the rail.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Standard drawings of CST-9 assemblies illustrate each of these items, confirming the completeness of the description.

Why Other Options Are Wrong:

Any single statement alone is incomplete; the sleeper assembly includes all these components working together.

Common Pitfalls (misconceptions, mistakes):

Confusing CST-9 pot sleepers with wooden or PSC sleepers; overlooking the tie bar and cotters as essential connectors.

Final Answer:

all the above