Study of Ballast Fouling in Railway Track Formations

This article presents an overview (requirements) of rail track aggregates, the ballast gradation adopted in railways in different countries and their comparison with Indian ballast gradation, drainage of rail track and ballast fouling in India. Further in situ ballast sampling, testing and ballast fouling quantification are also presented for typical track ballast. Ten ballast samples were collected from in and around Bangalore, India and fouling values were estimated as per international procedures followed for determining the fouling indices. Results show that fouling values of station tracks increase with time. Non coal/ore transport tracks and track on firm sub grade experience moderate fouling due to the break down of ballast and naturally occurring materials like dust, dirt, soil, etc. Fouling indices are specific to fouling materials and gradations. In this study it was found that the existing fouling indices are unable to reflect the representative fouling values for Indian railway ballast studied, hence alternate fouling indices are suggested for Indian railway ballast gradation. The article also presents an overview of the recent advancements in the identification of subsurface rail track problems using geophysical methods and conventional track monitoring and cleaning. The Indian railway follows coarser ballast gradation and conventional procedure to identify the rail track subsurface problems. Many advanced methods need to be experimented in Indian rail tracks to modernize the railway track foundations for the fast transportation of goods and passengers.