What is generally specified for a rail section?

The specification of weight per metre for a rail section is critical because it directly influences various aspects of rail design and performance. The weight influences the strength and durability of the rail, impacting its ability to withstand the dynamic loads imposed by trains. Heavier rails typically offer better stability and longer service life, as they are less susceptible to deformation under load.

Additionally, weight per metre is a key consideration for the overall structural design of the railway, including the supporting subgrade and track structures. Different rail weights are suited for different types of services, such as heavy freight versus lighter passenger traffic, guiding engineers in choosing the appropriate rail for specific applications.

Other specifications like width, material composition, and length are also important but are typically secondary to the fundamental need to define the rail's ability to carry loads, which the weight per metre serves to quantify.