Permanent-way fastenings: Bearing (base) plates are used to fix which rail–sleeper combination?

Introduction / Context:
Bearing plates (base plates) distribute load from the rail to the sleeper, reduce seat crushing, and provide better spike/clip anchorage. Knowing where they are used is vital for understanding sleeper performance and fastening selection.

Given Data / Assumptions:

• Wooden sleepers are susceptible to seat indentation.
• Flat-footed rails have a broad base suitable for plate-and-spike/clip fastening.
• Bull-headed/double-headed rails historically sit in chairs.

Concept / Approach:
On timber sleepers, flat-footed rails typically require bearing plates to spread load and protect the wood. Bull-headed/double-headed rails use iron chairs keyed to the rail and do not rely on simple bearing plates on timber. Cast-iron or concrete sleepers integrate the bearing surface within their design.

Step-by-Step Solution:

Verification / Alternative check:
Permanent-way manuals specify base plates under flat-bottom rails on timber to preserve sleeper life and maintain gauge.

Why Other Options Are Wrong:

• Double headed / Bull headed to wood: Typically use chairs, not plates.
• Flat-footed to cast iron sleepers: Seats are integral; separate bearing plates are generally unnecessary.
• None of these: Incorrect because Option A is standard practice.

Common Pitfalls:

• Confusing chairs with base plates; they serve different rail sections.

Final Answer:
flat footed rails to the wooden sleepers