IN2ZONE will design and test a prototype next generation transition zone solution that provides a step-change in track support conditions, thus reducing maintenance interventions. The new solution will combine the newest existing transition solutions with technological advances from other sectors, including recent advances in material science. The solution will be holistic, combining multiple advanced technologies to achieve an optimised whole system stiffness. One aspect of this holistic approach will be the design of new automatic irregularity correcting sleepers, formed from synthetic material, with optimised geometry and stiffness for transition zones. They will use a new correction system to self-correct vertical track geometry irregularities/faults, meaning maintenance activities are less frequent. Further, as part of the holistic solution approach, the new sleeper technology will be combined with new advances in ballast stabilisation and soil improvement. This combined solution will result in an optimised whole system stiffness. Further, the entire solution architecture will be modular to ensure the benefits are realised in minimal time.
In addition to the new design, an advanced resilience-based monitoring specification for transition zones will be developed. It will fuse datasets from multiple track sensors (e.g. smart ballast, sleepers, and geogrid) with vehicle sensors and satellite data. This will be achieved using edge computing and artificial intelligence, resulting in an Industry 4.0 approach for just-in-time maintenance.
A time horizon of around 40 years beyond the current state-of-the-art is targeted as suggested in the call document. The new design will be optimised using the latest advances in discrete and finite element numerical simulation tools, coupled with computational fluid dynamics. The transition zone concept will then be constructed and tested at full-scale in one of the world’s largest accelerated track testing laboratory facilities, to TRL5/6. This also gives a rare and valuable opportunity to develop and test the transition zone solution installation, maintenance and decommissioning, while also assessing long-term settlement behaviour. To add additional value, HAZID, LCC and RAMS will also be investigated as part of the project. Further, active steps will be taken to ensure the research compliments the related S2R-CFM-IP3-01-2020 call, and will address the public deliverables from complimentary S2R projects, including IN2TRACK2 and S-CODE.
IN2ZONE’s pan-European consortium comprises 7 stakeholders covering all areas of expertise necessary to execute the project, including three companies, two research Universities, one Infrastructure Manager and one Rail Association.
The average construction cost of a railway track in Europe is between €13-40m euros per kilometre. Post-construction, large costs are then subsequently incurred maintaining this infrastructure. A major source of track maintenance cost is transition zones, due to the high maintenance demands required to keep the track at the desired track geometry, thus ensuring passenger ride comfort and avoiding speed restrictions. According to Sasaoka and Davis, 2005, $200m is spent annually on US railways for track transition maintenance, while in Europe about €85m is expected. Transition zones therefore represent an area of major opportunity, with considerable potential to reduce both direct and indirect costs (e.g. resulting from train delays and loss of capacity) of maintenance.
Transition zones are intended to provide smooth train movement, minimizing the impact of stiffness changes that exist along the track. When a train is moving from an embankment towards a stiff structure, such as a bridge, tunnel or culvert, an abrupt change in the support stiffness occurs, which increases the dynamic wheel loads, and causes high track stresses. At the same time a differential settlement between the embankment track and structure starts to occur, generating differential track geometry, which causes an increase in the interaction forces between the train wheel and rail. This leads to a magnification of the differential settlement that, in turn, causes an increase in the interaction force, which again causes an increase in the differential settlement. This mechanism repeats itself until maintenance is performed. At this point, the initial track geometry is restored, and a new degradation cycle is initiated by the stiffness difference.
To solve these longstanding transition zone problems, IN2ZONE will design and test a prototype next generation transition zone solution that provides a step-change in track support conditions, resulting in a drastic reduction in maintenance interventions. To achieve this, new automatic irregularity correcting sleepers will be designed, that are formed from synthetic material, with optimised geometry and stiffness for transition zones. This will enable the transition zone solution to self-correct minor track geometry irregularities/faults, meaning maintenance activities are less frequent. These novel sleepers will be part of a holistic design, which also uses novel ballast stabilisation, soil improvement and resilient elements to optimise the change of stiffness across the transition. An advanced resilience-based monitoring specification for transition zones will also be designed, combining track, vehicle and satellite sensors. These datasets will be combined using data fusion, and use an artificial intelligence and an industry 4.0 approach to inform maintenance.
High Level Objectives The main aim of IN2ZONE is to develop the next generationof transition zone, which offers a step-change reduction in maintenancerequirements, compared to existing solutions. The associated high levelobjectives are:
1. Reduction in service affectingdelays due to fewer track geometry defects and associated failures (forexample, due to track settlement or a localised loss of rail support)
2. Increased network capacityin terms of more frequent trains and higher speeds, due to improved verticalgeometry and reduced degradation rate
3. Reduced lifecycle costsdue to a reduction in maintenance and extended operational life of the trackand associated assets
4. Reduction in noise andvibration at the transition locations, due to the provision of a sustainedsmooth transfer between areas of differing support stiffness
5. To provide a solution foroptimum and sustained track support conditions, that is compatible with thenext generation track solutions developed within IN2TRACK2 and the complimentaryCFM project