Container Wagon Research Articles

Freight container wagon modelling and simulation analysis due to braking

To improve the wagon brake performance and to investigate the wheel skidding on the rail during braking, the comprehensive rail freight wagon models with consideration of braking are generated by using the Gensys software package, which includes the masses of a wagon carbody, two bolsters, four sideframes, eight axle boxes and eight wheelsets. The nonlinear characteristics of secondary and the primary suspensions are considered among the mass connections. The tangential wheel-rail contact creepages and creep forces are calculated by a modified FASIM method with consideration of decreasing changes after saturation points. The brake type of air-pressed friction shoe on wheel tread surface is taken into account and the reference brake force profiles are considered with the characteristics of increasing friction coefficient with wagon speed decreasing. The wagon rolling resistance is also considered by using the equations used in Australian rail industries. The wagon braking stopping distance at an operation speed and the wheel slipping and skidding during braking situations can be simulated, and the effect of wheel-rail surface conditions (dry, wet, low coefficient friction (LCF) modifier and grease), wagon loading distribution, etc., to the braking performance can be examined, and the discussions on the wagon braking operation are given.

Lateral instability of three-piece bogie container wagon and effect of the loading distributions

Several models of a non-linear rail three-piece bogie container wagon have been developed by using GENSYS software to study the effects of the initial excitation conditions to the determination of rail wagon’s critical hunting speed and the trajectories and characteristics of the wheelset lateral movement during wagon hunting. The effect of uneven loading distribution on a container wagon to the wagon lateral instability is also investigated. Based on the simulation results, the wagon hunting is the type of bogie hunting, and the hunting behaviours are dependent on the initial excitation conditions and wagon speed. The initial excitation condition based on a certain initial lateral track irregularity can generate the full bogie hunting compared to the initial carbody’s lateral and yaw velocities that are the default widely used in the GENSYS setting. The two bogie lateral movement trajectories can have a phase of about 900 or be in-phase dependent on the wagon speed. The heavy loading on a bogie can improve the bogie hunting, and the uneven loading can change the hunting pattern.

Simulation analysis of the impact of container wagon pin configuration on the train loading time in the intermodal terminal

The article presents the issues of a container train loading at the land intermodal terminal. This issue was considered from the point of view of the distance covered by the loading devices and the duration of loading works, which was influenced by the arrangement of containers on the storage yard and the configuration of pins on the wagons. The conducted research was dictated by the small number of publications on loading an intermodal train, especially from the point of view of pin configuration on wagons. The vast majority of the literature is devoted in this field to marine intermodal terminals, which operating characteristics are different from inland terminals. The importance of this problem resulting from the growing turnover of containers transported by rail transport was also pointed out. The systematic increase of this type of transport and the depletion of the intermodal services' operating capability makes it necessary to improve the train loading process. For the purposes of the research, the issues of containers of various sizes loading onto wagons planning with various pin configurations were presented. A literature review was carried out in the field of train loading methods and strategies. A mathematical model was developed for the decision situation under consideration. The equations defining the most important elements of the considered problem were presented in the general form. This model was implemented in the FlexSim simulation environment. The constructed simulation model was used to develop 12 variants of the approach to an intermodal train loading. The train loading tests were performed both for the random arrangement of containers on the storage yard and for the random arrangement of pins on the wagons. The obtained results made it possible to determine how the knowledge of the arrangement of pins on the wagons influences the planning of train loading and increases the efficiency of loading devices.

Numerical simulations of the separated flow around a freight train passing through a tunnel using the sliding mesh technique

The main aim of this investigation is to analyse the flow around a freight train as it passes through a tunnel. The separated flow around the train nose is related to energy losses, lateral vibration, noise and streamline deviation, and it also influences the velocity magnitudes around the train. Such effects are expected to become more important with the prospect of increasing freight train speeds. The numerical simulations performed in this study use a Class 66 locomotive connected to eight container wagons, scaled to 1/25th, moving at a train speed of 33.5 m/s through a tunnel with a blockage ratio of 0.202. The k–ω model combined with a high advection scheme solves the governing equations on a structured hexahedral mesh using the sliding mesh technique. The pressure histories at the tunnel walls and train surface as well as the velocity field around the train were validated with experimental data obtained using a moving model. The longest separation bubble is found at the middle-height and middle-width of the locomotive due to extended corners at these regions. When the train enters the tunnel, the separation length is reduced by 32% at the roof and 31% at the sides, compared to open air. The maximum separation length is found at the sides of the train where it reattaches at 19% of the locomotive length, influencing the velocity peak at a short distance from the train surface. The larger the separation length, the higher the length/duration of this peak. When the train head is halfway through the tunnel, the nose velocity peak reduces by 30% compared to open air. The position of the nose inside the tunnel affects not only the slipstream velocity but also the velocity field at the tunnel portal and exit. These novel findings can be used as a benchmark for designing new freight train and tunnel shapes.

High-speed freight trains for intermodal transportation: Wind tunnel study on the aerodynamic coefficients of container wagons

The paper investigates the response to crosswind of a high-speed freight train for intermodal transportation, through wind tunnel tests. A 1:20 model of a freight train composed by an engine and two flat-car vehicles was instrumented with force balances to measure the aerodynamic coefficients of the flat-car plus container assembly and of the container alone. Aerodynamic coefficients strongly affects the train stability and the anchorage limits of the container itself.During the wind tunnel tests, eight different loading configurations were considered and aerodynamic coefficients were determined for yaw angles (i.e. angle between train and wind) ranging from 0° to 90°. Experimental results show the benefits in terms of drag reduction due to the presence of a laden vehicle upstream. As far as the rollover risk is concerned, the less critical condition is found for a vehicle preceded by a fully laden wagon and followed by an empty one. More in particular, at low yaw angles, the worst condition for a vehicle occurs when the wagon ahead is empty while, for yaw angles between 45° and 55°, which are the most critical for ‘low speed’ trains, the differences with respect to the other configurations reduce significantly.

Assessment of various turbulence models (ELES, SAS, URANS and RANS) for predicting the aerodynamics of freight train container wagons

This study presents an assessment of the capabilities of various turbulence modelling approaches —ELES, SAS, URANS and RANS—to predict the aerodynamic flow around a double-stacked freight wagon, both in isolation and within a train. The numerical predictions are compared with experimental measurements at the same Reynolds number to determine the accuracy of each model. Specifically, aerodynamic drag, front and rear surface pressures, planar velocity fields and skin friction lines are validated against the wind tunnel results. In particular, predictions from the ELES and SAS models show good agreement with the wind tunnel data, both qualitatively and quantitatively. Indeed, ELES predicts both the range and distribution of the rear-face surface pressure very closely, indicating that the separated flow is also likely to be well predicted. Both SAS and ELES predict the pressure drag of the multi-wagon configuration to within 2% of the experimental value. However, the steady RANS model predicts the trends in pressure drag in line with the experiments as the front and rear gaps are varied, even though individual drag predictions are considerably worse. Overall, the set of results establishes the benefits and deficiencies of using particular turbulence models to capture different aspects of freight train aerodynamics.

Swiss Split—a holistic approach to the distribution of containers to private sidings

Swiss Split is a rail service in Switzerland which distributes containers via conventional shunting yards directly from intermodal terminals to the final recipients’ sidings by rail. Today’s Swiss Split service is quite successful, but it still has several weaknesses that reduce its competitiveness compared to container distribution by truck. Thus, the two main research questions were: Which feasible improvements for container distribution by rail can be determined? In how far do these improvements increase the competitiveness of container distribution by rail compared to container distribution by truck? The research bases on previous analyses regarding the weaknesses of container distribution by rail in Switzerland. For each of the identified weaknesses, suitable improvements were developed. The effects of these improvements were supposed to have an impact on the efficiency and the quality of the services. The improvements were then assessed by applying a cost model for rail freight and truck transportation. For this purpose, today’s Swiss Split was modelled in a base case and the input data for the cost model (e.g., round trips per day for wagons, routing for the transports, train length and train utilisation) were changed according to the estimated effects of the improvements. To finally estimate the impact of the improvements on the SWL production schemes, an agent based simulation for SWL was developed and applied. The analysis of today’s Swiss Split distribution by rail showed weaknesses in the fields of rolling stock, transhipment terminal structures and the production schemes for SWL. Thus, a new container wagon has been developed to serve the sidings. The terminal structure has been improved by a new gateway terminal. The production schemes for SWL have been improved by applying a train-coupling-and-sharing network structure and an improved schedule structure for SWL trains. An agent based simulation software for rail freight has been developed to assess the improvements in the production scheme. At last, the new business model for Swiss Split has led to an integration of transhipment processes and rail distribution. In sum all of these measures have resulted in significant cost reductions for the container distribution by rail. The breakeven distance for Swiss Split compared to truck container distribution has been decreased from 140 to 70 km. Hence, using SWL for final distribution has proofed to be competitive to trucking even for rather short distances. This shows that rail freight can be competitive compared to road transportation if a holistic approach which tackles all weaknesses of the existing services is applied.

The ViWaS Project: Future-proof Solutions for Wagonload Transport

Rail transports of single wagons or wagon groups are an indispensable part of the transport chain, such as for the forestry and the chemical industry. However, high production costs and low quality standards have led to a continuous decline in market shares in recent years. In order to counteract this tendency, ten European companies and research institutions, covering the areas of rail transport and logistics, have combined their forces in the scope of the research and development project ViWaS (Viable Wagonload Production Schemes). The goal: Innovative and simultaneously practical solutions for a sustainable wagonload transport. The applicability of these solutions and their effects have been proven with the aid of business cases in terms of field tests and pilot operations. The following main innovations have been achieved within the ViWaS project:(1)Improved “last-mile” operating concepts incorporating hybrid locomotives and bi-modal shunting engines (by Bentheimer Eisenbahn, Fret SNCF and SBB Cargo supported by HaCon and NEWOPERA): The new production method for last-mile delivery is based on the idea of separating train movements and sidings shunting processes by deploying bimodal road-rail tractors. Processes within the sidings have been simplified; as a result costs for equipment and staff could be reduced considerably. Hybrid locomotives are fundamental in securing a seamless access to regional distribution rail networks. Potential cost advantages have been identified comparing different traction combinations of real-life transport chains.(2)Modular wagon technologies for a flexible and efficient use of resources (by Wascosa and SBB Cargo): In detail, three components have been developed up to prototype status: Wascosa's Flex Freight Car is a light container wagon with an accessible floor and thereby applicable for various transport purposes. The Timber Cassette 2.0 is a new superstructure for log wood transport that features foldable stanchions and can be used in combination with a container wagon. In case the Timber Cassette is not loaded, it can be removed and stacked at the terminal or on a container wagon. Empty runs will be minimized generating efficiency improvements. Additionally, SBB Cargo has developed the so-called Container Loading Adapter, another add-on to a container wagon. It facilitates container loading and unloading in sidings. SBB Cargo will deploy this new component within the “Swiss Split” production system, combining intermodal with wagonload transport.(3)Smart wagon telematics allowing improved tracking at reduced costs (by Eureka): A separate abstract “Smart Telematics Enabling Efficient Rail Transport” (Contribution ID 875) has been submitted for TRA 2016).4.A new simulation tool for planning and optimizing single wagonload networks (by ETH Zürich): WagonSIM is an agent-based simulation tool for rail freight networks to facilitate the optimization of SWL production schemes. It is based on the OpenSource software MatSIM. The tool models the routing of freight wagons according to the routes within the real SWL network. Therefore, the modelling of two network levels is required, the production network and the physical infrastructure.The ViWaS project is co-financed by the European Commission in the scope of the Seventh Framework Programme.

Freight rail transport governance: An international issue

Since the economic deregulation of freight transport operations internationally, it has been necessary to have a workable knowledge and an understanding of the types of freight wagons that can help to be instrumental in the efficient and effective market participation of rail technology in the freight transport market. The article identifies and describes the most commonly used rail freight wagons for commercial purposes internationally. The investigation has indicated that subsequent to the economic deregulation of freight transport, there are nine rail wagon types manufactured and commonly used internationally. They are: (1) covered wagon/van; (2) refrigerated wagon/van; (3) flat wagon; (4) tank wagon; (5) container wagon; (6) open wagon; (7) hopper wagon; (8) side stanchion and centre partition wagon; and (9) motorcar wagon. The study revealed that the following three factors mainly dictate wagon design: (1) characteristics of the freight to be transported; (2) physical railway characteristics; and (3) the type of freight terminals and handling equipment necessary to efficiently and effectively accommodate and support rail freight transport.

Three-dimensional derailment analysis of crashed freight trains

In this paper, the collision-induced derailment of freight trains was investigated. The collision between two identical freight trains occurring on a curved path rather than along a straight line was investigated. This is because from the point of view of safety against derailment this collision scenario is thought to be more critical than the scenarios defined in the European standard EN 15227. In this work, one of the trains is stationary and the other moving train collides at 36 km/h. Two kinds of container wagons were simulated. One is the two-axle freight wagon Kls 442. Another is the freight wagon Rmms 662 with two Y25 bogies. Simulation results demonstrate that in terms of safety against derailment the bogie wagon Rmms 662 was found to have better behaviour than the two-axle wagon Kls 442. In addition, this study points out that there are many contributory factors to the responses of freight wagons during a collision, such as curve radius, distance between bogie pivots and loading mass. The derailment phenomenon is less likely to occur, when freight trains collide on the curve with a larger radius. Besides that the characteristics of freight wagons with large axle loads, low centre of gravity of car body and appropriate static strength are favourable for the collided wagons in reducing the risk of derailment.

The aerodynamics of freight: approaches to save fuel by optimising the utilisation of container trains

Aerodynamic drag is approximately proportional to speed squared so the drag of slower moving freight trains has received less attention than that of higher-speed passenger trains. Key results of wind tunnel tests of European container trains were published in 1989 and are the basis for most assessments of drag of European container trains (American container trains usually have far higher drag due to double-stacking containers or transporting complete semi-trailers and were studied in research programmes at a similar time). The research reported here concerns a reappraisal of the European results and of more recent results obtained from the application of computational fluid dynamics modelling and the results of real-world and wind tunnel testing of the aerodynamics of container wagons. The paper presents empirical equations that can be used to predict the energy savings associated with different container loading scenarios within a fixed length train and the energy required for carrying aerodynamic features such as baffles or fairings. Illustrative examples are provided using data measured during freight operations. The effect on drag of side winds and their speed distributions are included as are representative vehicle speed profiles. Most previous authors have ignored both side winds and end effects; it is shown that the effects of these are opposite but of similar magnitudes so the results of these authors remain valid.

THE EVALUATING METHOD OF THE CONTINUATION RELIABILITY OF THE CONSTRUCTION LIFE OF RAILWAY TRANSPORT OF THE CHERNOBYL NPP

A methodical approach to the reliability estimation and service life prolongation of the railway carrier vehicle design, included into the bulk container wagon TK-8, and intended for transportation of exhausted nuclear fuel by rail tracks of the alienation zone is described. The results of work performed and the analysis of real operation conditions are presented.

Automated shunting of rail container wagons in ports and terminal areas

The development of intermodal container transport is hampered in part by the cost associated with the shunting of trains in marshalling yards, inland and port railway terminals. Many new technologies have been developed in the past decade, but have still not been applied because of high capital investment costs, lack of sufficient market demand and uncertain rates of return. The key for increasing the competitiveness of intermodal container transport by rail is the operation of heavy haul container trains between port and inland railway terminals more frequently with fast, flexible and automatic transhipment, shunting and coupling of container wagons. The operation of self-driven railcars equipped with automatic centre coupling on terminal tracks, which can also be train-hauled on conventional hinterland railway lines, would enable a reduction of shunting and transhipment time and costs in intermodal container terminals by more than 30%.

Theoretical Investigation of Wheel/Rail Non-Linear Interaction due to Roughness Excitation

A study is presented of the non-linear dynamic interaction between a wheel and rail, excited by rough-ness on the wheel and rail contact surfaces. A moving irregularity model is used to represent the wheel/ rail interaction process in the time-domain. A low order multiple degree-of-freedom system is developed to approximate the infinite track for numerical simulations. The effects of the non-linear contact on the wheel/rail dynamic interaction are investigated through calculations, analysis and comparisons with the results from a linear contact model. The difference between the non-linear and linear interactions is found to be small if the roughness level is not extremely severe and a typical static contact preload exists. The difference increases for low preloads or for high roughness amplitudes. For example, if the wheel and rail surfaces are in good condition (r.m.s. amplitudes of roughness below 15 mm), the linear model can be used without significant error for all static loads down to 25 kN (equivalent to an unloaded container wagon). When the track is corrugated with an r.m.s. amplitude of 25 mm, good agreement between linear and non-linear models is obtained for static loads of 50 kN and above, typical of passenger stock or loaded freight vehicles, but differences of up to 4 dB in one-third octave force levels are found at 25 kN. Differences between the linear and non-linear models are found to occur when the r.m.s. roughness amplitude is more than 0.35 times the static deflection of the contact zone; significant loss of contact occurs at amplitudes about 1.5 times greater than this.

VALIDATION OF DYNAMIC SIMULATIONS OF RAIL VEHICLES WITH FRICTION DAMPED Y25 BOGIES

Theoretical modelling of a container wagon fitted with Y25 bogies was compared to actual track test data, using the VAMPIRETM Rail Vehicle dynamics modelling software. The Y25 bogie makes use of load sensitive friction damping, and has highly non-linear behaviour. Elements of the vehicle design which were important in predicting vertical and lateral ride were identified and are described in the paper. Wheel profile, accurate modelling of primary and secondary suspensions, and coefficients of friction of the wheel/rail interface and suspension friction faces, were found to be particularly important to ride prediction. The behaviour of the vehicle was very input dependent. It was possible to produce a good correspondence between track test and model results for both vertical and lateral behaviour.

VALIDATION OF DYNAMIC SIMULATIONS OF RAIL VEHICLES WITH FRICTION DAMPED Y25 BOGIES

Abstract Theoretical modelling of a container wagon fitted with Y25 bogies was compared to actual track test data, using the VAMPIRETM Rail Vehicle dynamics modelling software. The Y25 bogie makes use of load sensitive friction damping, and has highly non-linear behaviour. Elements of the vehicle design which were important in predicting vertical and lateral ride were identified and are described in the paper. Wheel profile, accurate modelling of primary and secondary suspensions, and coefficients of friction of the wheel/rail interface and suspension friction faces, were found to be particularly important to ride prediction. The behaviour of the vehicle was very input dependent. It was possible to produce a good correspondence between track test and model results for both vertical and lateral behaviour.