In rail traffic, existing and planned standards dealing with the design of single, highly loaded structure components are not based on the latest knowledge and do not offer a reliable guarantee against damage. Compared to other transportation systems, a lack of basic knowledge generally exists in railway design. Such knowledge and experience are decisive prerequisites for a reliable design and the specification of safe structures for long-term usage.
Ensuring the competitiveness of the rail vehicle industry requires innovative solutions and methods to reduce system costs, shorten development times and increase safety and transport capacity. Rail infrastructure is very important in this regard.
Lifetime and endurance strength are mainly determined by the following parameters:
- operational loading combined with special event-loading (wheel-flats);
- existing design of the complete trackbed system and its components;
- influence of materials;
- environmental conditions;
- quality assurance monitoring and maintenance schemes.
The interaction between vehicle and infrastructure results in complex stresses and damage mechanisms:
- material fatigue under highly dynamic loads;
- damage to rails by rolling contact due to abrasion, wear and tear, plastic deformation in the surface zone;
- trackbed settlements.
Such damage may lead to considerable danger and a reduction in safety, as well as to a loss of comfort and a decreased driving performance. It will at least lead to an impairment of availability and an increase in maintenance expenditure.
It is mandatory to first solve some major track-related problems before being able to increase the technical harmonisation for vehicles and hence the potential of these vehicles to be used in other cities. The advantages will be enormous: higher residual value of vehicles, higher scope for vehicle leasing, higher vehicle production series and hence reduction of manufacturing costs and production lead times.
The SPURT project led to infrastructures, which are in an acceptable condition for ensuring seamless transportation. The infrastructure will no longer be the bottleneck for optimal operation. The vehicle speed should be as high as possible (this is, in general, not an issue for the vehicle but depends on the condition of the infrastructure).
The objective of the project was to study (problem identification and solution) track-related problems. The major track-related problems that were studied are:
- the reduction of the track degradation in time for ensuring a minimum track quality level;
- the avoidance of derailment for ensuring safety at all times;
- the improvement of the wheel/rail interface for reducing maintenance;
- the minimisation of noise and in particular structure-borne noise and vibrations.
The project identified effective solutions for existing and future vehicle types, albeit that some vehicle (wheel set) adaptations might be recommended or required.
Data were collected about the tram lines in different European cities (i.e. the types of rail, types and numbers of curves/crossings, the current quality of the rail including any history of damaging growth, date of laying) and data about the vehicles running on these tracks (i.e. type and number of vehicles, profiles and wheel quality).
Comprehensive technical knowledge was gained on flange-climb derailment mechanisms through experimental data and numerical results. Numerical data were collected concerning the response of tramcars to degraded track conditions. This methodology showed which of the infrastructure requirements (maximum acceptable irregularity levels) are compatible with vehicle safety and operating conditions.
Finally, data concerning the correlation between service loads and damaging growth on rails and wheels were collected.
The SPURT project focused on the development of solutions of the complex situation in the urban rail transport industry, concerning the compatibility and interoperability issues among present or future networks. Rail mass transit vehicles, defined as 'trams, light rail and metros' very often do not behave as expected when running on the existing rail infrastructure, although the vehicles may well be fully compatible with the specifications of the buying authorities and they may well have passed the acceptance tests. A major challenge therefore was that a particular vehicle might perform well in one particular network and the same vehicle could show important problems in another network. Many operators have different types of vehicles and different types of track systems in their network. They all want the different existing and future vehicles to perform well in their complete existing and future network. This was one of the reasons why most vehicles today have been built to local specifications, which led to a continuation of the incompatibility and interoperability issues.
Exploitable results were developed with joint forces of the SPURT project partners, summarised as:
New methodologies considering the:
- material and component requirements to maximise lifetime of wheels and rails in operation; in combination with optimal maintenance procedures (best timing) and to minimise grinding of wheels in order to reduce lifecycle cost and maintain vehicle safety;
- infrastructure requirements (maximum acceptable irregularity levels) compatible with vehicle safety and corresponding reference data.
Comprehensive technical knowledge of:
- rolling contact fatigue phenomena through experimental data and numerical results. This includes experimental data collection concerning the behaviour of specimens and to determine optimal material combinations;
- flange-climb derailment mechanism through experimental data and numerical results - with numerical data collection concerning the response of tramcars to degraded track conditions.
Data collections concerning:
- optimal materials combinations for wheel and rail based on the numeric model and the specimens' results;
- sensitivity analysis on the influence of the main parameters involved (tramway layout, track irregularity, wheel diameter, W/R profiles, vehicle speed and vehicle characteristics) on VV/R dynamic loads;
- wheel-rail contact forces corresponding