What are sleeper ties primarily made from?

Sleeper ties, also known as railway ties or sleepers, play a crucial role in the stability and longevity of railway tracks. The primary materials used in the construction of these ties are wood, concrete, or steel.

Wooden ties have been a traditional choice, known for their ability to absorb vibrations and provide flexibility. Concrete ties are increasingly popular because they are durable, resistant to weather elements, and require less maintenance than their wooden counterparts. Steel ties offer high strength and durability, particularly in heavy-load situations or areas with extreme conditions.

In contrast, while rubber and plastic are used in some rail applications, they do not typically make up the main body of sleeper ties. Cement and asphalt are more related to the construction of the track bed rather than the ties themselves, and glass and fiberglass are not suitable for heavy railway applications due to their lack of strength and durability under loads. Therefore, the combination of wood, concrete, or steel as materials for sleeper ties makes this option the correct answer.