Train Marshalling Research Articles

Research on Comprehensive Optimization of Train Marshalling and Parking Scheme of Intercity Railway Based on Operation Cost

Research on Comprehensive Optimization of Train Marshalling and Parking Scheme of Intercity Railway Based on Operation Cost

Virtual Dynamic Marshalling of Trains under Severe Epidemic Situation

In the context of the global epidemic, urban rail transit has the risk of spreading the virus. Taking Beijing Metro Line 1 as an example, this project establishes a dynamic model of train variable marshalling by studying passenger behavior and virus transmission, aiming to explore more intelligent marshalling mode, optimize transportation organization, and improve the flexibility of train marshalling and dispatching of urban rail transit, so as to improve its transportation efficiency and reduce the station personnel density, Then reduce the risk of disease infection of passengers in the process of taking urban rail transit under the background of the outbreak. The results show that: Dynamic marshalling technology can significantly improve the transport efficiency of urban rail transit trains and effectively control the risk of infection of passengers.

An Investigation of Influence of Windshield Configuration and Train Length on High-Speed Train Aerodynamic Performance

The aerodynamic performance of four train models with different windshield configurations (i.e., internal and/or external) in three train marshalling modes (i.e., 3, 6 and 8-car groups) was numerically investigated in this study. The train's airflow characteristics at Re=2.25×106 were determined using the shear stress transport (SST) k- turbulence model. The results were validated by comparing the pressure distributions and drag forces on the streamlined heads with experimental data. The difference in windshield configuration and train length has a substantial influence on the train’s flow field and surface pressure distribution. For the trains with internal windshields, due to non-uniform geometry, the flow is separated and vortices are formed at the windshield area. The boundary layer profile increases with the increased train length, and its thickness varies with windshield configurations. Asymmetric vortices are formed in the wake at a distance close to the tail car’s nose, except for trains with external windshields. The reduction of the flow velocity as the train length increases causes a reduction of the low pressure near the tail car’s streamline transition, thus causing a decrease in the tail car’s drag and lift forces. Consequently, for trains with external windshields, the head car’s drag increases, whereas the total train drag reduces significantly as the train length increases. Therefore, employing external windshields in all the inter-carriage gap sections, irrespective of the train length, demonstrates a good ability to reduce future train’s aerodynamic drag.

Quality Analysis of Railroad Train Shunting Operation Plan Using the Intelligent Body Model

Shunting work is an important component part of railway transport production and is an important link in realizing the train marshalling plan and the train operation map, accelerating the rotation of vehicles, and completing the task of transport production. With the present, the gradual construction of passenger dedicated lines and high-speed train operation bring a new dawn to railroad transportation on the one hand, but on the other hand, high-speed train operation makes the process of train operation more complicated, and the safety hazards and uncontrollable factors of trains are higher than before. Compared with existing lines, passenger dedicated lines put forward higher requirements on the performance of train operation and dispatching system, requiring better real-time, intelligence, and interactive response characteristics of the train operation and dispatching system. The construction of passenger dedicated lines and the increase in train operation speed have put forward higher requirements for safe, on-time, and high-efficiency train operation. The train operation scheduling system is one of the cores of intelligent railroad transportation system, which is the guarantee of safe and on-time train operation. This requires the search for new control strategies to meet the requirements of high-speed train operation and multiple objectives of safety, punctuality, and comfort. Train operation scheduling is a typical distributed system. At present, there are still problems in the safety of railway shunting operations, such as disconnection in management and implementation, failure to revise some rules and regulations, frequent occurrence of obstacles in equipment and facilities, and substandard quality of operators. Therefore, it is necessary to make a systematic analysis of the current situation of railway shunting safety and propose countermeasures and measures. By studying the structure of intelligent body and multi-intelligent body theory, it decomposes the influencing factors of railroad shunting operation, designs the intelligent body model of each element, and applies it in train shunting operation to improve the quality of railroad shunting operation.

Hill-starting a heavy haul train with a 24-axle locomotive

Head-end trains are more efficient than Distributed Power trains in terms of train marshalling. This paper studied an unprecedent real-world engineering problem to hill-start a long heavy haul train at a 1.2% up-hill gradient by using a 14400 kW 24-axle AC electric locomotive (maximum traction force 2280 kN). Longitudinal Train Dynamics simulation were conducted to assess five potential driving strategies in terms of train speed and in-train forces. The simulation results show that the locomotive can hill-start the heavy haul train with 80% traction throttle. However, maximum locomotive coupler forces (1840 kN) exceeded coupler knuckle yield strength (1780 kN) of the original coupler system design. Sensitivity analyses were conducted to assess the implications of train starting resistance for train speeds and in-train forces. The study recommends increasing coupler knuckle yield strength to 2450 kN. The increased knuckle yield strength is still lower than that of the chassis, which is able to meet system design requirement; it also enables the locomotive to hill-start by using traction throttles of 80, 90, and 100% with safety factors of 1.3, 1.2 and 1.1 respectively.

The dynamic amplification factors for continuous beam bridges along high-speed railways

In this paper, the dynamic amplification factors (DAFs) of high-speed railway continuous girder bridges are studied. The vehicle-bridge interactions (VBIs) of 13 concrete continuous girder bridges with spans ranging from 48 to 130 m are analyzed, the influences of the train speed, the train marshalling and the bridge fundamental frequency on the DAF are investigated, and the DAF design standard for high-speed railway bridges is discussed. The results indicate that for the continuous beam bridge whose fundamental frequency is less than 3.0 Hz, the maximum DAF is no more than 1.15; while for the bridge examples with a fundamental frequency larger than 3.0 Hz, the maximum DAF reaches 1.25 because the resonance occurs at high train speed. The empirical formulas of the DAFs in the Japan Railway Technical Research Institute (JRTRI) code could provide a conservative estimation of the DAFs of high-speed railway continuous bridges.

Influences of marshalling length on the flow structure of a maglev train

In this paper, transient numerical simulations of maglev trains of different marshalling lengths (2, 4, and 8-car group trains) were conducted in the open air and without wind. This was done by solving the three-dimensional incompressible Navier-Stokes equations using an SST K-ω double-equation IDDES turbulence model. The results were compared with the results of wind tunnel experiments to verify the feasibility of numerical simulation. The results show an increase in the marshalling lengths of the train affects the flow above and below the train. With the increase of the marshalling length, the position of the flow separation in the tail car is advanced. The turbulence generated by the average shear on the x, y-plane and the x, z-plane as a component of the turbulence of the wake region increases. The region that produces non-vorticial vorticity in the main vortex becomes narrow and moves towards tail car. The structural analysis of the wake indicates that the wake structure of the 8-car group train is quite different from the other two groups. Both the time-averaged slipstream and the gust analysis show that the maximum expected slipstream velocity at the track-side increases as the train marshalling length increases. At the platform height, the change in vertical position of the wake vortex structure of the 2, 4, and 8-car group trains caused the difference of the shear flow regions. This is why the maximum expected slipstream velocity generated by the 4-car group train at this position is largest. As the marshalling length of the train increases, the time-average drag and lift force coefficient of the tail car have a significant negative correlation.

The influence of reduced cross-section on pressure transients from high-speed trains intersecting in a tunnel

Alleviation of the pressure transients caused by high-speed trains intersecting in a tunnel with partially reduced cross-section is investigated by numerical simulation. The RNG k-ε turbulence model and hybrid grid are adopted for the numerical simulation, which is validated by the moving model test. Two factors, the length of reduced section (L) and the train marshalling number, are considered to analyse the alleviation effect. The results show that, for reduction of the pressure transients induced by the intersection of three-car marshalling trains, the location of the change in cross-section is supposed to be near the location of the maximum value of the initial expansion wave (L → 240 ​m). In addition, for four-car marshalling trains intersecting in a tunnel of L ​= ​240 ​m, the excavation volume of the tunnel (tunnel volume) decreases by 14.4%, and the average pressure amplitude on the train surface decreases by 7.9%. Especially the pressure amplitude at the measurement point in the streamlined area of the tail car decreased by 28.6%. The reduced section tunnel has a good effect on decreasing the pressure transients around train body and the tunnel excavation volume (construction cost), which helps the tunnel design process.

On the hardness of palletizing bins using FIFO queues

We study the combinatorial FIFO Stack-Up problem. In the delivery industry, bins have to be moved from conveyor belts onto pallets. Given is a list Q of k sequences of labeled bins and a positive integer p. The goal is to palletize the bins by iteratively removing the first bin of one of the k sequences and putting it onto a pallet located at one of p stack-up places. Each of these pallets has to contain bins of only one label, bins of different labels have to be placed on different pallets. After all bins of one label have been removed from the given sequences, the corresponding stack-up place becomes available for a pallet of bins of another label. The FIFO Stack-Up problem asks whether such a processing is possible. The FIFO Stack-Up problem is known to be NP-complete even if the sequences of Q contain together at most cQ=6 bins per pallet. This implies that the problem is also hard if all bins of every pallet are distributed to at most dQ=6 sequences. In this paper we strengthen the hardness to the cases cQ=5 and dQ=3. We also show the hardness for the practical case where the number of sequences is smaller than the number of pallets, and we point out differences to related problems like 3D Bin Packing and Train Marshalling.

A Novel Dynamic Programming Approach to the Train Marshalling Problem

Train marshalling is the process of reordering the railcars of a train in such a way that the railcars with the same destination appear consecutively in the final, reassembled train. The process takes place in the shunting yard by means of a number of classification tracks. In the Train Marshalling Problem (TMP), the objective is to perform this rearrangement of the railcars with the use of as few classification tracks as possible. The problem has been shown to be NP-hard, and several exact and approximation algorithms have been developed for it. In this paper, we propose a novel exact dynamic programming (DP) algorithm for the TMP. The worst-case time complexity of this algorithm (which is exponential in the number of destinations and linear in the number of railcars) is lower than that of the best presently available algorithm for the problem, which is an inclusion-exclusion-based DP algorithm. In practice, the proposed algorithm can provide a substantially improved performance compared to its inclusion-exclusion-based counterpart, as demonstrated by the experimental results.

The Case Study of Pseudoexcitation Method Combining Self‐Adaptive Gauss Integration in Random Vibration Analysis

The pseudoexcitation method (PEM) can improve efficiency of random vibration analysis. However, for large‐sized structures with wide frequency range of response, the workload of calculation is heavy if conventional integration methods, such as trapezoidal integration, are used to combine with the PEM to calculate structural response. In such case, self‐adaptive technology is induced to combine with the PEM to form an efficient method for solving random vibration. During calculation, this method can realize the adaptability of random excitation to actual structural response, identify automatically critical frequency intervals of random excitation, and process intelligently the identified critical frequency intervals and noncritical frequency intervals. Based on the identified frequency intervals, Gauss integration is carried out to obtain response results with random characteristics. The computational efficiency and accuracy of PEM‐SGI are verified by wind‐induced performance of the slender bridge tower. Finally, the influence of damping ratio of the bridge structure and train marshalling on vehicle‐bridge coupled system is investigated to further verify the application of the proposed method. Results show that the efficiency of solving random vibration can be improved by the present method.

Field study on high-speed train induced fluctuating pressure on a bridge noise barrier

The pressure variations induced by a CRH380A EMU on a 2.15 m high bridge noise barrier are investigated in a field measurement. The familiar fluctuating pressure time history curves and the peak-to-peak pressure (ΔP) distributions attributing to the train head on the barrier surfaces are presented. A comparison of the positive head pulse pressure is made between the measurement results and the data calculated by empirical equations in EN 14067-4. Furthermore, the influences of train speed, train running lines, locations of measurement points, train marshalling length and environmental wind speed on ΔP are analysed. The results indicate as the train speed increases, the corresponding time intervals of ΔP decrease gradually, whereas their slopes become increasingly steep. For a CRH380A EMU, the aerodynamic length of the train head is between 7.63 and 7.64 m, which differs from the physical length of a realistic train with 12.00 m. Along the noise barrier from bottom to top, the ΔP values on the inner surface decrease with the increase of height, while these values on the outer surface increase. Taking the wind direction into account, the ΔP values are a little higher when the high-speed trains run against the wind direction.

The train marshalling by a single shunting engine problem

We consider the problem of marshalling a train from a number of rail cars that are distributed throughout the classification bowl of a shunting yard. In contrast to most other contributions we do not consider marshalling based on repeated roll-ins, but marshalling by shunting engine. This is also a common process alternative at shunting yards that has not yet received much attention from the scientific community. The goal is to find the optimal route for this shunting engine that respects all constraints applicable to movements in a shunting yard. We propose a Mixed Integer Programme (MIP) under consideration of single-block trains. A block refers to rail cars that share the same destination. Then we conduct a series of numerical experiments and show that the solutions of the MIP improve by 10% on average when compared to those produced by a Real-World-Heuristic that is designed to approximate the current marshalling practice. Finally, we statistically derive relationships between selected problem instance characteristics and the expected marshalling effort that can be useful for practitioners and operators of shunting yards.

Research of Train Flexible Marshalling Transportation Organization for Urban Rail Transit

This paper introduces the basic concept of flexible marshalling, summarizes the existing basic types of train marshalling transportation organization mode, contrasted to various types of applicable situation and advantages and disadvantages. Based on the analysis of the applicable conditions of flexible marshalling transportation organization mode in passenger flow and circuit, and analyzes the important factors which influence train flexible marshalling transportation organization from four aspects of passenger flow, facilities, operation efficiency and passenger service level. At last, some suggestions are put forward for train flexible marshalling transportation organization scheme design.

Paris Underground Metro Dust: Workers Exposure and Health Study

MAA3-O-04 Introduction: High concentrations of dust (fine particle) recently have been found in underground metros, including Helsinki, London, New York, Stockholm, and Paris. Then Paris public transportation company (Régie Autonome des Transports Parisiens, RATP) is currently performing a study to evaluate the potential health risks associated with metro dust. On a daily basis, about 4 million commuters and a quarter of RATP workers (more than 10,000) are exposed to underground subway air. However, subway dust differs from ambient particulate matter in size and chemical composition. It is therefore not clear whether subway dust leads to a similar toxicity. Methods: The present work concerns the second phase of an air quality study that aims at describing air quality indicator levels within 4 types of occupations, 3 train types and workplace characteristics. Personal monitoring was used to evaluate time weight average exposure levels for a sample of 54 underground workers. Air quality was ascertained to measure its contamination in fine particulate matter (PM2.5 and PM10) levels and metal composition, poly- and monocyclic aromatic hydrocarbons, organic and elementary carbon, various organic solvents, crystalline silica, asbestos and human-made mineral fibers, and endotoxins and molds. Work activities have been detailed in a diary. Results: For most of the considered indicators, the measured levels were very low. Particulate matter seems to be the only pollutant of interest. Lower PM10 and PM2.5 levels were measured within booth station agents as compared with train marshalling, train conductors, and controllers. PM10 levels also were smaller among tire-wheel subway line workers. No difference was observed between iron-wheel and RER workers. Copper dust levels were greater among tire-wheel subway lines workers than for other type of lines. On the other hand, lead levels were greater among iron-wheel subway line workers, whereas iron, manganese, chromium, and nickel levels were greater among RER workers. No significant link was observed between tobacco smoke exposure and air quality indicators levels in this preliminary analysis. Discussion and Conclusions: Workers' ambient air is characterized by important levels of metal dust. This preliminary analysis will need to be confirmed during the third and last step of the study on 280 additional personal air sampling randomly assigned within the whole subway network. A health study is currently performed to evaluate the potential health risks associated with Paris metro dust exposure. Pulmonary functions and respiratory and cardiovascular symptoms will be measured in 4000 RATP agents, including 2000 underground and 2000 surface workers, half of whom are commuting by metro or RER and will be used as controls. Exposure, health status, and health risks will be assessed according to different activities (commercial, logistic, and control agents and drivers), job sites (stations/lines), train types, and time spent underground. The health risks of surface workers commuting by metro may be extrapolated to estimate risks of other commuters. This surveillance system requires a crafted communication plan to facilitate understanding and clarify expectations of employees, unions and directors.

Fuel Consumption of Freight Trains Hauled by Diesel Electric Locomotives

The cost of railway diesel fuel has become an increasingly high proportion of railway operating expenses. The paper analyzes the generation and utilization of rail horsepower in freight train operations. The effects on fuel consumption of variations in several parameters including train consist, car weight, gradient, average speed, meet strategy, throttle control, locomotive axle arrangement, and train marshalling are examined. Estimates are made of the value, in terms of fuel cost, of weight reduction of freight cars and of selective train marshalling.