Ballast degradation can cause poor drainage, settlement and reduced lateral stability, which adversely affect railroad track safety and performance. Two indices are commonly used in the North American railroad industry to quantify the level of ballast degradation. These are (i) Fouling Index (FI) and (ii) Percentage Fouling (PF). Identifying these two traditional indices involve ballast samplin...

Abstract Ballast fouling in railroad substructure is detrimental to railroad track effectiveness and its structural capacity. Ground penetrating radar (GPR) provides a rapid, effective and continuous approach to assess railroad substructure condition. However, unknown ballast dielectric constant and unclear interface between clean and fouled ballast limit the GPR assessment accuracy. In this st...

This research examined the feasibility of applying Time Domain Reflectometry to the task of broken rail detection. The key innovation is to regard the track as a two-wire electrical transmission line, and then apply the same electrical pulse/echo technique that is commonly used to locate breaks and shorts in electrical cables. The aim of the proposed locomotive-mounted system is to allow each t...

Ballast, typically comprising large sized aggregate particles with uniform gradation, is an essential layer in the railroad track substructure. Functions of ballast include facilitating load distribution and drainage, maintaining track geometry and track stability, and providing track resilience and noise absorption. Throughout its service life, ballast goes through changes in gradation and par...

The seismic failure behavior of railroad ballasts in response to earthquakes was analyzed using Discontinuous Deformation Analysis.Several sinusoidal waves with different frequencies and accelerations were inputted into the discontinuous numerical model of a railroad ballast ,which consists of an assemblage of polygonal crushed stones,rails,sleepers and a roadbed .The dependencies of railroad f...

Railway transition zones between open track and rigid structures such as bridges and culverts often experience differential movements due to abrupt changes in track stiffness and complicated dynamic loading effects. Such conditions commonly lead to track geometry issues, consequently increasing the magnitude of impact loads at these areas. This in turn leads to excessive degradation of ballast ...

This paper evaluates the different AREMA gradations currently in use for their effects on both ballast void space and load carrying performances using a discrete particle analysis computational technique called Discrete Element Modeling (DEM). The effect of gradation on aggregate assembly volumetric properties was first studied. Full-scale ballast layers with common gradations listed in AREMA s...

In North America, most rail corridors are constructed using ballasted track. Monitoring the ballast support condition and improving upon current sub-structure/ballast maintenance strategies will ensure safe railroad operations. However, it is inherently difficult to evaluate the pressure distribution at the sleeperballast interface. Researchers at University of Illinois at Urbana-Champaign (UIU...

This is a review of walking tasks in the railroad environment, and the injuries that result from slips, trips, falls, or other acute or even non-traumatic exposures. The lack of federal regulations for railroad walkways has led several states to develop and enforce their own regulations. Support from the research literature for such regulations has come from biomechanical studies of the effects...