Stages of ballast compaction and breakdown: (a) new ballast placement, (b) initial ballast compaction, (c) well-compacted ballast typical of consolidated track, and (d) ballast breakdown.

Ballast and sleepers. (Managed by Dr. Antonis Zervos) Introduction. The primary component of ballasted track, on which maintenance is concentrated, is the ballast itself. Ballast must fulfill the two competing requirements of achieving high permeability for rapid drainage and high stiffness for spreading train loads efficiently to the sub-base.

To investigate these aspects, a series of large-scale triaxial cyclic tests were conducted on railway ballast. To investigate the influence of grading and frequency on the resilient modulus of railroad ballast, laboratory data from previous work were analysed and discussed. It was observed that the resilient modulus of ballast decreased with an ...

The inspection and maintenance of track ballast are fundamental tasks for the preservation of the condition of railway networks. This work presents an application based on a low-cost solid-state ...

Therefore, a 50 kg ballast sample containing a total of 584 ballast particles sieved according to the current Chinese code (TB/T for the first-class gravel ballast, and the grading curve of the ...

The deterioration of track ballast is mainly reflected in the fragmentation of ballast particles and the evolution of grading. The repose angle of the ballast is the internal friction angle, reflecting the shear strength of the track ballast. The angle of repose of 158 ballast samples with varying gradation parameters was tested by conducting hopper flow tests …

Sieving characteristic and the permissible grading limits for the crushed rock ballast of 31.5/63 mm fraction and of the grading classes E and F

Ballast gradation is a prime factor for the stability, safety and drainage of tracks. A specified ballast gradation must provide the following two key objectives:

The classification criteria and the application of proposed ballast fouling index to predict the ballast-cleaning cycles is also presented.

Ballast is one of the major sources of construction and maintenance costs for railway tracks. Ballast particle grading critically influences the mechanical behaviour of ballast. In this research, a comparative study has been made to assess the grading performance stipulated in the Bangladesh Railway Ballast Specification (BRS).

The development of qualitative relationships between relevant ballast properties and its performance in track is a vital step towards analysing ballast on a life cycle costing basis. Field and…. Expand. 12. Semantic Scholar extracted view of "Recommended Ballast Gradations" by B. Indraratna et al.

A relatively optimal grading for ballast was proposed to improve its deformation and degradation performances under cyclic loading with high frequency, …

ballast life. The consensus of the Ballast and Subgrade Working Group of the AAR (J) is that decisions on ballast

This paper presents the results from a laboratory study and explores the potential to achieve this through improving the ballast grading and reducing the ballast shoulder slope.

The results show that the type of recovered life-expired ballast used in this study has good performance and similar strength to fresh ballast despite having reduced surface roughness.

The increase of sub-ballast thickness by 5 cm in an all-granular track can improve the sub-grade service life by only 20% to 50%.

Thus, significant benefits would accrue from a more robust track design having a longer service life and reduced maintenance requirements. This paper presents the results from a laboratory study and explores the potential to achieve this through improving the ballast grading and reducing the ballast shoulder slope.

The specified top size and grading (or grain size distribution) of railroad ballast affects its method of production and its performance in track. Both parameters affect any economic evaluation of ballast; as such it is essential to optimize both. The main source for ballast gradings in North America is the American Railway Engineering ...

A recommended procedure for ballast selection and a new grading specification for railway ballast are presented. These recommendations are based on experimental and field results developed over the period 1971-78. The ballast selection procedure offers an improved sequential screening process to eliminate undesirable materials, and permits the ...

Ballast tank de-scaling may consider the use of magnesium. Surface preparation method chosen depends on the amount of coating failure and the service life intended.

The review shows that regarding ballast selection means and criteria, the number and type of quantitative indicators varies greatly between countries.

The results show that the type of recovered life-expired ballast used in this study has good performance and similar strength to fresh ballast despite having reduced surface roughness. The …

The specified top size and grading of railroad ballast affects any economic evaluation and its performance in track. Both parameters affect any economic evaluation of ballast; as such it is essential to optimize both. The main source for ballast gradings ...

To investigate this possibility, a series of high-frequency cyclic triaxial tests has been conducted to examine the effects of confining pressure and deviator stress magnitude on ballast ...

This paper presents the results from a laboratory study and explores the potential to achieve this through improving the ballast grading and reducing the ballast shoulder slope.

A series of large-scale repeated-load triaxial tests on a crushed metasandstone railway ballast is described. The effects of different gradings on degradation and accumulation of permanent strain are investigated. The material tested was a mechanically strong ballast aggregate with grading curves similar to the envelope curves in the Norwegian railway …

A total of three spatial distributions of the ballast aggregates within the tank were investigated, by emptying out and filling up thrice the tank with the same material. The geometric information on the ballast grading obtained from the simulation-based regression model was compared to the actual grading curve of the ballast.

GUIDELINES FOR COATING MAINTENANCE & REPAIRS FOR BALLAST TANKS AND COMBINED CARGO/BALLAST TANKS ON OIL TANKERS

Ballast layer has weighty share in the lifecycle costs of railway track. The strict standards and maintenance rules of ballast grading significantly contribute to the ballast costs.

Civil Engineering questions and answers. A railway ballast grading table, before loading and after two years of loading are given below. (a) Draw the particle size distribution curves of the ballast before and after loading in one figure indication both curves. (b) Calculate the breakage index (Bf) based on Marsal's Method (c) Calculate the ...