A short survey on modern Track maintenance methods is given, concentrating on the developments in recent years. The ongoing refinement of the machinery should be shown as the influence of ITsolutions should. On top the economic view to the Track infrastructure is briefly demonstrated. Further developments in Track hardware solutions must respect the obtained high level of Track work mechanization. However, with respect to presentation time some other ongoing developments unfortunately are not discussed. Prominent amongst those are: the advent of high grade rail steels like heat-treated perlitic steels, the experiments with bainitic steels and the introduction of hydraulically driven turnouts with special high-speed-prone rail geometry or the latest machine sets for general subgrade rehabilitation.

Development of an optimized strategy for the maintenance of Iranian railway Track maintenance in a form of management system was made in this research. Through reviewing the current maintenance management system in the USA, Europe and Asia as well as investigating the characteristics of railway structure and current maintenance approaches in Iran, a new algorithm was made in order to improve efficiency of maintenance decision system and maintenance planning in Iranian railway industry. The practicability and reliability of the new maintenance algorithm (model) were evaluated by applying the new proposed algorithm in a railway line in Tehran province. It was shown that the new proposed maintenance management system (algorithm) is effective in providing an optimized maintenance strategies and plans. It was also shown that Track operation can be evaluated by sensitivity analyses of the proposed model.

This paper deals with the modeling of a vertically coupled vehicle-slab Track using finite element method. The slab Track system is represented by a two layer Euler-Bernoulli beam model including rail and concrete slab. The vertical stiffness of Track bed is assumed to be random variable using Monte Carlo simulation. The vehicle is simplified as a multi-body system with 10 degrees of freedom. The accuracy of the simulation is verified by deterministic and random approaches as well. Sensitivity analyses on the various parameters such as slab thickness, coefficient of Track bed stiffness, vehicle velocity are performed. It is demonstrated that the uncertainty in Track bed stiffness has a major effect on rail and slab deflections. From a practical point of view, the obtained results of the present study can be utilized efficiently in the analysis and design of slab Track systems.

Railway is a major transportation system for mass transport at high speed to connect large cities. Recently many concerns have been focused on developing new type of train and increasing the maximum speed moreover to cope with the congested situations and environmental problems of railroads and roadways. One of the most important structural problems to meet the social demands would be to solve the dynamic interaction of vehicles, the rail and bridge, evaluate the running safety, and assume excellent riding comfort at high-speed operation. The dynamic response of railway bridge under moving load has been studied both theoretically and experimentally for many years. Recently, more sophisticated models that consider various dynamic characteristics of the moving vehicle have been used. Traditionally in studying the dynamic response of a vehicle-bridge system, two sets of equations of motion can be written, one for the vehicle and the other for the bridge or rail. It is interaction force existing at the contact point between the two subsystems that make the two sets of equation coupled. One feature with this kind of contact problem is that the contact points move from time to time. To solve these two sets of equations, procedures of an iterative nature can generally be followed one drawback of this approach is that the computation involved in the iteration process can be significantly large. The converge rate is likely to be low, when dealing with the more realistic case of a bridge bearing a series of vehicles in motion. From literature review, it is clear that most of the existing procedures cannot be efficiently adopted in the analysis of general vehicle-Track-bridge systems. In this paper, a finite element formulation to solve the dynamic response of vehicles, the rail and a general bridge is presented. The interaction between wheel and rail is completely considered here. A mechanical model to describe the interaction between the wheel and the rail that is connected directly with the bridge is described. For the vertical and rolling motion, constraint equation to connect wheel-set and the rail are given.The equations become time-dependent since wheel-set move on the rail at high speed. For the transverse and yawing motions, constitutive equations to describe the relationship of interaction forces and relative velocities between wheel and rail are given in a form to be treated in the finite element solution procedure. The numerical method of solving the equation of the motions of vehicle-Track-bridge systems effectively under the constraint and constitutive equation to express the interaction between the wheel and rail is discussed.A computer program, DTVBI has been developed for the nonlinear analysis on vehicle- Track-bridge interactions. Numerical examples are demonstrated to assume the validity and effectiveness of the proposed method. Case study carried out on concrete three-span bridges with continuous girders by using mechanical model and presented analytical method.The results of calculations showed that a Track effect on running comfort of passengers (lateral & vertical accelerations of rolling stocks) is very important. Track effects on bridge dynamic responses depend on their span length and in bridges with spans smaller than 25m have considerable effect, however, in bridges with larger spans have less effect.

The growth of railway lines has caused engineers to seek to increase the efficiency of the ballasted railway Track, and for this reason, they are looking for an increase in the maintenance intervals and a lower life cycle cost. In high-speed railways and lines with high traffic volume, especially railways with stiff and soft subgrade, the issue of line settlement is one of the challenging factors. According to the methods introduced to strengthen the subgrade so far, the use of geogrid is one of the conventional methods to reduce settlement and maintenance operations, which today requires more investigation in its optimal selection. In this article, an attempt has been made to investigate the effectiveness of geogrid to reduce stresses on the subgrade, sub-ballast layer, and ballast layer, and to explain how to choose it based on the technical parameters. In this study, the types of geogrid and the effect of mesh size, applied stress, and its effect on soil resistance have been investigated and the method of achieving the appropriate selection of geogrid has been suggested. Studies show that by using geogrid, the vertical settlement and horizontal movement of the railway panel can be reduced by 70%.

The main design criteria of ballasted railway Tracks include rail deflections, rail bending stresses, rail wheel contact stresses, sleeper bending moments and ballast sleeper contact pressures. Various criteria have been defined for the design of ballasted railway Tracks due to the various mechanical properties of Track components and their complex interaction. Therefore, the railway Track design is a difficult and time-consuming process. These complications highlight the need to focus attention on the necessity of a thorough investigation into the effect of the Track and rolling stock parameters on the design criteria. In an attempt to overcome this problem, a sensitivity analysis of the main railway Track design criteria was conducted in this study. Consequently, the roles of Track and rolling stock parameters (including Track modulus, sleeper spacing, train speed and axle load) in the design of railway Track were investigated for various Track design criteria. The research findings provide new and practical suggestions in the analysis and design of ballasted railway Tracks.

Rail transportation system plays an important role in the development of the economies of the countries. This system will be worn over time by operation and weather conditions and will require maintenance. One of the goals of this operation is to keep the Tracks in an acceptable condition and prevent their excessive deviation from the optimal situation. Railways maintenance and repair management system has been studied and implemented to optimize activities and reduce related costs. Such systems have used various techniques to predict the future state of failure. Choosing the best maintenance policy is the goal of these systems. For policy making, the best and most cost-effective option, life-cycle cost analysis is required. In the following, with the help of the Markov prediction model, the life cycle cost (LCC) model is suggested for rail and ballast. In the end, it was found that the main costs in the ballast part are renewal costs and the Track unavailability costs. The effect of renewal tonnage on these two costs is far higher than other costs. As you can see, the lowest ballast life cycle cost in the range of 100 to 150 million gross tons. In this study, assuming annual tonnage (16 million gross tonnages) as previously mentioned, it results a renewal life of about 6 to 10 years. This value for the rails is from 500 to 540 million gross tons, which is equivalent to 30 to 35 years.