Cast-iron “pot” sleepers: Which configuration correctly describes the arrangement of bowls (pots) and tie bars in pot-type sleepers?

Introduction / Context:
Before widespread adoption of concrete sleepers, many systems used cast-iron “pot” sleepers on ballasted track. Understanding their physical arrangement helps in recognizing historic track forms and their limitations.

Given Data / Assumptions:

• Pot (bowl) elements made of cast iron.
• Tie bar connects individual pots to maintain gauge.

Concept / Approach:
Pot sleepers typically consist of two separate cast-iron pots placed beneath the two rails. A tie bar connects them to preserve the gauge and transmit loads, while packing is done under each pot.

Step-by-Step Solution:

Verification / Alternative check:
Historic track diagrams show two pots aligned under the rail seats with a transverse tie bar.

Why Other Options Are Wrong:

• Multiple bowls chained by one tie bar: Not the standard pot sleeper arrangement.
• Two bowls plus one central: Not a recognized conventional configuration.
• Single bowl with twin bars: Does not provide stable two-rail support.

Common Pitfalls:

• Confusing pot sleepers with CST-9 and other cast-iron sleeper types with different geometry.

Final Answer:
Two bowls placed under each rail and connected together with a tie bar