Research into enhanced tracks, switches and structures

The project have tree parts.

The first one are about switches and crossings we have analysed failure modes, analysed new components and technologies. New and novel inspection techniques and sensors have analysed. All of this are made in a holistic whole system way to reduce the LCC-cost.

The second one significantly improve the performance of the track structure. This relates to costs, robustness and performance, in a RAMS-sense. To this end, innovative solutions in the form of methods, products, processes and procedures will be required.

The third one is about structures, bridges and tunnels. Develop faster and more accurate methods for inspection and assessment of tunnels and bridges including improved repeatability, reproducibility, quality and effectiveness. Develop new techniques for repair, strengthening and upgrading which results in reduced traffic disruption and fast installation with short track access time.

"Switches and Crossings
Steps toward a whole system model framework for switches & crossings have been taken. As an example of implemented results is the prediction of crossing geometry evolution (due to plasticity and wear) under operational loading. This modelling (which includes a multitude of numerical tools), allows a crossing design that (after a short time) ""wears in"" to the optimal geometry. This will significantly increase the operational life of the crossing. The economic benefit will depend on the operational conditions, the base case (e.g. the “unoptimized geometry” to compare towards) and local rates for maintenance and replacements including secondary costs.
It was found that opportunity exists to prevent a significant proportion of faults relating to switches by self-adjusting. The faults which remain, or are uneconomical to prevent, may be detected early using a range of sensing, which is mature in the railway industry. Automatic self-adjustment can be fitted to the majority of switches. A cost-benefit analysis of self-adjusting switches and crossing infrastructure with built-in monitoring, considered over the life-cycle of the asset indicating an 8% annual rate of return was performed in In2Track.

Track structure
Slabs with a twofold objective for the fibres has been developed. The first objective is as a traditional reinforcement. The second objective is to deteriorate the interface when replacement is necessary. In the case studied, the deterioration has been triggered by microwave application. The ability to deteriorate the slab provides a major benefit in required time and resources when a slab needs to be replaced; a slab that can be broken up by fibre debonding needs much less efforts for demolition. The related cost savings will depend on the local conditions of track, labour etc. They should be possible to estimate with rather good precision for specific conditions.
Building on work in In2Rail, a method for repair of discrete rail defects using line welding has been further investigated. In particular, the propensity for subsurface initiated rolling contact fatigue at the weld has been investigated in depth using numerical simulations. Through this simulation-based validation, the risk has been shown to be moderate, which makes the method suitable for implementation in field demonstrators. Due to its efficiency and reduction of operation time, the method was in In2Rail shown to be a cost-efficient method to handle severe rail surface defects. The research in In2Rail further confirms the potential of the method.

Structures
In2Track has investigated inspections using high definition images of tunnel lining paired with precise positioning, lidar scanning and an autonomous digital image correlation software capable of automatically detecting significant changes in the external aspect of the tunnel lining. Several test runs have been made in the project. The technology brings economic and capacity related benefits and also improvements in workers safety.
Optical measurement methods – ground based and un-manned aerial vehicle (UAV) mounted – have been used to test the applicability of several image-based technologies in the creation of digital twins, detection of damage and identification and tracking of changes in geometry and structural behaviour of bridges. In addition, trials using un-manned aerial vehicles for bridge inspections have demonstrated that the data is of improved quality compared to the traditional methods and provides sufficient information to the asset owners to assess the overall condition of the bridge. The benefits of these enhanced inspection methods include reduced traffic disruption, decreased costs and enhanced workers safety."

Switches and Crossings
This relation was established through numerical simulations supported by field measurements. To establish this relationship is crucial, since it is the basis for predictive maintenance of crossings – maintenance related to settlements are resource intensive and should not be carried out more than required. On the other hand, if the increased loads due to settlements lead to increased crossing deterioration, the resulting maintenance needs increase drastically. The research has established that well-maintained crossings do not have settlement rates that exceeds those of the adjacent track. In addition, it has provided means to establish under which crossing conditions settlements are likely to increase. The savings due to the increased maintenance precision will depend on the operational condition. Under given operational conditions it can be quantified using local rates for traffic disruptions, personnel, material etc.

Track structure
As shown in In2Track, bituminous sub-ballast layers can be used to improve load distribution over the track substructure and thereby reduce settlements. Research in In2Track further shown that common bituminous mixtures are suitable for railways. Further, a guideline design chart for track bed design using asphaltic formation has been developed. The ability of reducing settlements using the relatively simple measure of inserting a bituminous layer would lead to significant savings especially in areas with difficult geotechnical conditions.

Structures
In2Track has analysed and tested enhancement of old masonry arch bridges by using concrete liners, cross ties and fibre reinforced polymer pattress plates. Old steel bridges have had single structural elements or whole deck sections replaced by statically equivalent fibre reinforced polymer elements. In addition, using carbon fibre reinforced polymer plates to reinforce stringer to floor beam connections has been studied and experimentally tested. The research has a massive impact on capacity and economic in that it allows bridges to be upgraded instead of a much more costly and time demanding replacement.

Periodic Reporting for period 4 - IN2TRACK (Research into enhanced tracks, switches and structures)

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