Cyprien Hoelzl

• MSc Civil Engineering
• PhD Student at ETH Zurich

Railway infrastructure is a crucial asset for the mobility of people and goods. The increased traffic frequency imposes higher loads and speeds, leading to accelerated infrastructure degradation. Asset managers require timely information regarding the current (diagnosis) and future (prognosis) condition of their assets to make informed decisions on...

The health monitoring of railway networks offers a means to ensuring high-quality service, avoiding safety risks, and optimally planning maintenance actions to minimize life-cycle costs. Monitoring of the substructure is particularly linked to the tracking of degradation, which often stems from water infiltration, causing moisture accumulation in t...

Understanding the dynamics of the interaction between railway vehicles and tracks is essential for forecasting vehicle and track conditions and performing maintenance actions to preserve the safety of railway infrastructure. In this work, physics-based models are deployed to predict the dynamic response of railway vehicles to track alignment and ir...

Partially Observable Markov Decision Processes (POMDPs) can model complex sequential decision-making problems under stochastic and uncertain environments. A main reason hindering their broad adoption in real-world applications is the unavailability of a suitable POMDP model or a simulator thereof. Available solution algorithms, such as Reinforcemen...

According to the International Union of Railways, railway networks count more than one million kilometers of tracks worldwide, a number that is to rise further as the goal is to promote rail transportation as a sustainable means to face the challenge of increased mobility. However, such a vast expansion further necessitates efficient and reliable i...

Optimal maintenance planning for railway infrastructure and assets forms a complex sequential decision-making problem. Railways are naturally subject to deterioration, which can result in compromised service and increased safety risks and costs. Maintenance actions ought to be proactively planned to prevent the adverse effects of deterioration and...

The optimal maintenance planning for railway systems forms a complex sequential decision-making problem. Optimal maintenance actions ought to be configured on the basis of updated rail condition estimates. To this end, structural health monitoring solutions can be used for reliably tracking the condition of railway infrastructure. However, the meas...

An informed assessment on the condition of the railway infrastructure forms a prerequisite for establishing efficient predictive maintenance schemes. On-board monitoring (OBM) offers a continuous means for assessment of railway tracks, typically relying on exploitation of axle box acceleration measurements. However, OBM measurements come with uncer...

Partially Observable Markov Decision Processes (POMDPs) can model complex sequential decision-making problems under stochastic and uncertain environments. A main reason hindering their broad adoption in real-world applications is the lack of availability of a suitable POMDP model or a simulator thereof. Available solution algorithms, such as Reinfo...

Monitoring information can facilitate the condition assessment of railway infrastructure, via delivery of data that is informative on condition. A primary instance of such data is found in Axle Box Accelerations (ABAs), which track the dynamic vehicle/track interaction. Such sensors have been installed on specialized monitoring trains, as well as o...

On-board acceleration measurements bear significant potential for the early detection of damage to railway infrastructure components. Condition assessment forms a complex problem in this case, due to the mobile nature of the On Board monitoring (OBM) solution, and the uncertainties associated with the rail-wheel contact dynamics, a lack of knowledg...

Structural Health Monitoring (SHM) describes a process for inferring quantifiable metrics of structural condition, which can serve as input to support decisions on the operation and maintenance of infrastructure assets. Given the long lifespan of critical structures, this problem can be cast as a sequential decision making problem over prescribed h...

Intelligent data-driven monitoring procedures hold enormous potential for ensuring safe operation and optimal management of the railway infrastructure in the face of increasing demands on cost and efficiency. Numerous studies have shown that the track stiffness is one of the main parameters influencing the evolution of degradation that drives maint...

The increasing demand in mobility forms a major challenge for modern cities, even more so when examined under the prism of transition from traditional to CO2-free mobility. Railway infrastructure forms a main carrier for the mobility of people and goods and a salient component of critical infrastructures. The increased traffic frequency in urban tr...

The continuously increasing demand for mobility results in increased loading of the Swiss railway network, which is further associated with higher wear and deterioration of the rail infrastructure. Safety relevant surface defects on railway tracks, such as squats, have acted as an important driver of rail replacements in Europe. The early detection...

Critical to railway infrastructure assessment is the tracing of interaction between railway vehicle and track.This is a non-trivial task characterized by non-stationary dynamics appearing due to changing operational conditions. To ensure reliable dynamic characterization of rail infrastructure, we propose a modeling methodology of locally non-stati...

Wind turbines operate under non-stationary dynamic loads to which they constantly adapt by regulating the orientation of the blades and the rotor, as well as the generator torque resulting in characteristic responses (i.e. operating regimes) over a range of operating conditions. We propose a method to classify the operating regimes from coarse reso...

Wind turbines comprise structures of highly complex dynamics, operating under significant variations in environmental and operational conditions. Effective monitoring and fatigue prediction algorithms for these structures require an accurate representation of their dynamic response on both the short-and long-term scale. The latter may be achieved i...