The reduction of the weight of freight wagons is a key element in improving the competitiveness of rail freight and, thereby, obtaining the societal and environmental benefits of increasing the modal share of rail freight. Lighter weight freight vehicles have a number of advantages such as:
- The improved ratio between the weight of the payload and the vehicles’ tare in a train contributes to increasing the efficiency of the train and allow trains of the same total weight to carry more freight.
- They allow a greater payload to be carried by a vehicle within the same limits of the overall vehicle weight, as imposed by infrastructure managers, increasing thus the vehicle capacity and overall train productivity;
- The lower vehicle-track interaction forces reduce the impact on the infrastructure and on the vehicle itself, contributing to reducing maintenance costs and increasing the LCC.
Motivated by the necessity and opportunity for change in freight rail transport, the INNOWAG approach proposes technical solutions for freight vehicles to improve the sustainability, competitiveness and availability of freight rail, as well as increasing capacity. INNOWAG will develop a high performance lightweight design concept for freight vehicles facilitating cheaper faster, more logistics capable, and improved quality freight services. Whilst Work Stream 2 focuses on lightweight vehicle design, other design innovations will be considered with respect to noise reduction, manufacturing cost, and interoperability. The critical aspects related to the novel conceptual design will be validated through modelling and simulation techniques, as well as through laboratory testing.
The objective of Work Stream 2 is to identify and assess suitable candidate materials and structural shapes to be developed into concept designs for lightweight structural components, subassemblies and parts for lightweight freight vehicles. This will be followed by the validation of the concept designs through modelling and structural testing of components, and testing of the selected materials resistance to environmental factors.
The methodology proposed by the INNOWAG project for developing the lightweight design concept comprises five specific steps, which are presented below.
As a first step, the research activities in Work Stream 2 will start with a benchmarking of existing technologies related to structural lightweighting solutions, including the specifications and requirements for lightweight material concepts for freight vehicles. The analysis will be carried out using state-of-the-art methodologies and tools (e.g., Granta CES Selector), with the most promising classes and types of materials being selected and assessed.
The second step involves the development of novel multi-functional modular concept designs for lightweight components, subassemblies and structural parts of freight vehicles, using suitable options from the range of candidate materials identified in the previous step. INNOWAG will investigate the possibility of designing vehicle lightweight structures using novel structural profiles developed by industry and integrating smart design and manufacturing solutions. Most lightweighting solutions focus on traditional materials such as steel and aluminium, although the trends and growth of the market show that vehicles manufactured from high performance composite materials may become an attractive alternative. The proposed lightweighting methodology in INNOWAG will not only be applied to the wagon design, but will also extend to provide innovative lightweighting solutions for bogie structure.
The third step will consist of the application of novel material structure solutions, including composite structures, in the novel design concept. INNOWAG will further investigate the integrity of these solutions, focusing on the optimisation of the vehicle structure design within the constraints of the standards relating to structural and dynamic performance of vehicles.
The fourth step involves the modelling and analysis of the developed design concepts. This will be done through dedicated computer simulation tools. The analyses and simulation outcomes would support the validation of the novel design solutions with respect to the standard requirements and specifications defined by the benchmarking step. The analysis will include FEA and dynamic analysis of the wagon and bogie designs according to EU standard regulations and UIC leaflets. The study will also consider fatigue analysis for critical design concepts involving particular joining solutions (e.g., welding of special steels, joining of dissimilar materials, etc.). A vehicle dynamic analysis will be also carried out to evaluate the impact of novel design solutions. It will also address key dynamic performance indicators for the validation of the novel design concept.
Finally, the innovative solution proposed by INNOWAG will require specific testing for the validation of the proposed design solutions. The following test categories are considered for the proposed innovations:
- Quasi static tests; this can include structural strength tests of structural elements under static loads and it also includes impact tests.
- Dynamic and fatigue tests; the tests will be carried out under dynamic loading scenarios and will also include Thermo-Mechanical Fatigue (TMF) testing to determine the total lifetime of some components in the INNOWAG design.
- Non-destructive tests NDT; include techniques for the estimation of the joint quality. The quality of joints will be evaluated for new joining techniques and dissimilar joints.
- Material resistance test; includes laboratory tests for given environmental conditions and effects caused by specific bulk loads (acid, petrochemical products and salt), and resistance tests against impacts.
Data obtained through these tests will be used to support the proposed material selection, design and manufacturing solutions.
Considering the priorities and trends identified by previous work, as well as the relevance to the lightweighting objective, the INNOWAG Work Stream 2 is currently focusing on the following types of wagons:
- Flat wagon enabling container transport – classes R and/or S (or a combination of these types allowing the modification of a platform wagon into a covered one);
- Open self-discharge wagon class F for bulk materials (e.g., Faccs type);
- Cereals ‘hopper’ wagon class U or T (e.g., type Uagps, Uagpps, Tdgs, etc.)