Running Speed Of Trains Research Articles

Mechanical Analysis of Soundproof Plate with Function of Wind Load Reduction and Experimental Verification Using a Full-scale Prototype

Soundproof walls are typically installed along viaducts to reduce trackside noise. Soundproofing systems are being built increasingly higher as train running speeds increase and the number of tall buildings near railway lines grows. This often leads to increase wind load and moments exerted on the walls. This study proposes a new type of soundproof plate systems that would not require drastic reinforcement of the viaduct. The system, called SSRW (soundproofing systems equipped with a mechanism of reducing wind load), deflects wind load, thus maintaining the viaduct safety in strong wind conditions. Magnetic attractive force controls the movement of the SSRW soundproof plate; magnetic field analysis was used to calculate the magnetic attractive force. The authors also performed load tests and wind tunnel tests, and they measured the SSRW's soundproofing properties according to Japanese Industrial Standards.

Multi-objective optimization of the streamlined head of high-speed trains based on the Kriging model

As the running speed of high-speed trains increases, aerodynamic drag becomes the key factor which limits the further increase of the running speed and energy consumption. Aerodynamic lift of the trailing car also becomes the key force which affects the amenity and safety of the train. In the present paper, a simplified CRH380A high-speed train with three carriages is chosen as the model in order to optimize aerodynamic drag of the total train and aerodynamic lift of the trailing car. A constrained multi-objective optimization design of the aerodynamic head shape of high-speed trains based on adaptive non-dominated sorting genetic algorithm is also developed combining local function three-dimensional parametric approach and central Latin hypercube sampling method with maximin criteria based on the iterative local search algorithm. The results show that local function parametric approach can be well applied to optimal design of complex three-dimensional aerodynamic shape, and the adaptive non-dominated sorting genetic algorithm can be more accurate and efficient to find the Pareto front. After optimization the aerodynamic drag of the simplified train with three carriages is reduced by 3.2%, and the lift coefficient of the trailing car by 8.24%, the volume of the streamlined head by 2.16%; the aerodynamic drag of the real prototype CRH380A is reduced by 2.26%, lift coefficient of the trailing car by 19.67%. The variation of aerodynamic performance between the simplified train and the true train is mainly concentrated in the deformation region of the nose cone and tail cone. The optimization approach proposed in the present paper is simple yet efficient, and sheds lights on the constrained multi-objective engineering optimization design of aerodynamic shape of high-speed trains.

Examination of Speed Control for Reducing Warning Time in Level-Crossing Control for CBTC System

Some level-crossing control methods have been proposed as a subsystem of the Communications-Based Train Control (CBTC) system. In this method, the warning starts according to the forecasted time when a train reaches the level crossing; the forecasted time is calculated on the basis of the speed and detected position of the train. Therefore, we have analytically clarified the quantitative relations among the train's position at the start of warning, train-running speed, and maximum train speed, which have not yet been shown. In this paper, we propose a speed-control method for reducing the warning time according to the train-speed characteristics in the train level-crossing control for the CBTC system. In addition, this method has been proposed for reducing the warning time when a train comes from the opposite direction according to the conventional level-crossing control. Therefore, we also propose the application of the speed-control method to the case when a train comes from the opposite direction. In addition, we show the effect of the reduction in the warning time by applying this method for speed control without train delay.

Numerical Simulation of Aerodynamic Noise Generated by High Speed Trains

Aerodynamic noise becomes more and more significant and sometimes could be predominant as the running speed of high speed trains increases. As a result, aerodynamic noise has to be taken into consideration during the design of high speed trains. In present work, the research on aerodynamic noise of the high speed train with a speed of 300 km/h has been performed. The nonlinear acoustics solver (NLAS) approach is adopted to study the aerodynamic noise in the near field of the high speed train. With the use of an acoustic surface, the research on the aerodynamic noise in the far field has been carried out by solving the Ffowcs-Williams/Hawking (FW-H) equation. At first the method validation is performed through a two-dimensional backward step case, which shows excellent agreement with experimental results. The characteristics of the flow field dominate the generation of aerodynamic noise, therefore the flow field is firstly analyzed, including the head, the rear, and the inter-coach spacing of the train. By use of probes in specific regions on the surface of the train, the contribution of different parts of the train to the aerodynamic noise is discussed. Meanwhile, the far field feature of aerodynamic noise is also studied by placing probes in the far field. Based on the above analysis, the aerodynamic noise performance of the specific high speed train is assessed.

Design of Train Traction Calculation Software Based on Traction Materials

The main work of this paper was the following: based on various effects on train running imposed by operation conditions, showing the effect to train running speed by ramp; under different situation, forming automatically calculating control value of train running process through the highest speed tactics of traction and designing automatically calculating train traction calculating software under the single-particle model. The calculation of train running speed and its zonetime is the main function of train traction calculation software. Lastly, utilizing automatically calculating function, train running process of different teams, limited speed and running route is calculated and the validity, correctness and practicability of the automatic train traction calculation software are testified according to the contrastive analysis of automatically and manual cases.

New Monitoring System for Wheel/Rail Contact Force without a Special Wheel-Set

A new measuring method introduced in this paper can measure contact forces between wheel and rail without special wheel-set with slip rings or telemeters. In this method the lateral contact force is measured from the lateral distortion of wheel measured directly by several non-contact gap sensors. Normal and longitudinal contact forces are also measured from the deflection of spring or the strain of parts of the bogies except special wheel-set. This new method, unlike the conventional method, is able to store the data everyday on every curve of commercial lines, which change according to friction coefficient and train running speed and so on. In this paper the authors describe the new measuring method without strain-gauge-equipped wheel-set, estimations of comparing the new method and the conventional method, and data analysis of measurements by commercial service trains. Practicable use of this new method enables us to easily obtain the statistical data of derailment coefficients with an on-board measuring method. Statistically analyzing the variation of rail-lubrication conditions and characteristics of wheel-rail contact force on every curve with this new system can help to improve track conditions for maintenance.

The Study of Automatic Train Operation (ATO) System

As a sub-system of ATC system, the ATO subsystem is a very important part, which is the technical measure that can raise the train movement level of urban track transportation (on time, comfortably, energy-saving). Using LabVIEW embedded control system to simulate the ATO system with two levels of Fuzzy Neural Network. By studying and differencing the input data in preceding network, the best operating condition of the train in the specific position can obtain, according to which the latter network infers train's running speed under current condition.

THE SETING OF THE ALLOWED SPEED ON THE STRETCH OF THE GAUGE RENOVATED WITH MODERN GAUGE MACHINES

The article presents the outcomes of experimental and theoretical research on determination of allowed train running speeds on the segments of track repaired in conditions of long-time section closure, with the use of track maintenance machines RM-80 (or a similar one), VPR or Dynamic Track Stabilizer, and gives the guidelines on development of technological processes of track repair with use of the above-mentioned machinery.

Signalling blocklayout and strategy of train operation for saving energy in mass rapid transit systems

An approach for assisting the design of fixed-block signalling system of mass rapid transit (MRT) systems by optimising the block layout and running speed code of each signalling block between any two neighbouring stations is presented. The object is to achieve minimum energy consumption with maximum train capacity. The apporach preadjusts the running speed restriction of trains to avoid overspeeding on an alignment. At the same time it can also shave-off unnecessary speed changes to improve passenger comfort. The concept of equiblock signalling is used to assist this research. Considering the effect of gradients and the limits of minimum headway of an ATO system and average train speed, a genetic algorithm is applied to determine the shortest length, speed codes and positions of signalling blocks. Single train running dynamics between stations is simulated based on the signalling system of an MRT system with various aspects, positions and numbers of signalling blocks through acceleration and jerk limits. An heuristic search is used to seek out the combination of train running speed code of each signalling block for energy saving.

1403 レール波状摩耗の成長過程に関する考察 : 第5報-横クリープにより生成される波状摩耗(OS9 接触メカニズム)

Rail head corrugations appearing in the sharp curve sections are mainly caused by slip and stick between rail and wheel. The formation mechanism of corrugation due to lateral creep has been reported in the former researches. In this report, the growing process of rail corrugation due to lateral creep is described. The influences of train running speed, friction coefficient between rail and wheel and wheel load on the growing of corrugation are simulated. From the simulation results it is found that, friction coefficient between rail and wheel has great influence on the growing of corrugation. Improvement of friction condition between rail and wheel is effective in reducing rail corrugation.

ACTUAL STATE AND SUPPRESSION OF A LATERAL FORCE INDUCED AT GUARD RAIL IN RAILWAY TURNOUT

The guard rail existing in railway turnout receives a large lateral guiding force from running wheels. This force is one of the important factors limiting the running speed of trains at turnouts. The paper describes: (1) The results of a series of running tests on Kosei line, which clarify the actual condition inducing the force; (2) A theoretical study performed by a simulation method using a dynamic rolling stock model; and (3) The countermeasures to suppress the force at the guard rail.