Two-block concrete sleeper (twin-block) basics: Which of the following dimensions and weights correctly represent each individual block of a two-block concrete sleeper?

Introduction / Context:
Two-block (twin-block) concrete sleepers consist of two reinforced concrete blocks connected by a steel tie bar. Their block dimensions and unit weights must be realistic for handling, installation, and design calculations. Overstated or understated values can signal incorrect data.

Given Data / Assumptions:

• Each listing claims to represent each block of a twin-block sleeper.
• Typical handling weights for a single block are well below 200 kg to allow practical installation.

Concept / Approach:
Field experience and catalog values indicate each block generally weighs on the order of several tens of kilograms to around a hundred kilograms, not 200–280 kg. Combined sleeper assembly weights vary with gauge and design but remain manageable for mechanized handling.

Step-by-Step Solution:
Check plausibility: options (a), (b), (c) give per-block weights exceeding 200 kg, unrealistic for individual block handling.Examine dimensions: the sizes listed correspond to large monoblock footprints rather than single twin-block elements.Therefore, none of the options accurately represents a standard per-block specification.

Verification / Alternative check:
Manufacturer datasheets for twin-block sleepers show each block weight typically around 70–120 kg depending on design, far less than 215–280 kg claimed.

Why Other Options Are Wrong:

• (a), (b), (c): grossly overestimate per-block weight and/or list unlikely dimensions.
• (e): appears more plausible in weight, but the dimensions are not standard; since the question asks for correct standard data, it is safer to reject all inconsistent entries.

Common Pitfalls:

• Confusing overall sleeper assembly weight with the weight of each individual block.

Final Answer:
None of these.