alépítmény

Alépítmény is a Hungarian term used in railway engineering to describe the substructure of a railway track. It encompasses all the layers beneath the track ballast, which in turn supports the rails and sleepers. The primary function of the alépítmény is to distribute the loads from passing trains to the underlying subgrade.

The alépítmény typically consists of several layers. The uppermost layer, immediately below the ballast, is often a granular material known as the sub-ballast or crushing layer. This layer helps to prevent the finer ballast particles from migrating downwards and protects the layer beneath from deformation. Below the sub-ballast is the formation layer, which is usually a compacted earth or gravel layer. This layer forms the structural base of the trackbed and is designed to be stable and impermeable. The deepest part of the alépítmény is the subgrade, which is the natural ground or engineered fill material upon which the entire track structure rests.

Proper construction and maintenance of the alépítmény are crucial for railway safety and operational efficiency. A well-designed and maintained alépítmény ensures track stability, prevents excessive settlement, and contributes to a smooth and comfortable ride for passengers. Issues within the alépítmény, such as poor drainage or inadequate compaction, can lead to track irregularities, increased maintenance costs, and potential derailments.