This master thesis explores the optimization of concrete through girder bridge design using a
parametric design approach, focusing on reducing material usage and optimizing for costs and environmental performance through iterative design improvements. The research addresses a critical need in the Netherlands, where numerous bridges are approaching the end of their design life and require replacement or renovation, by allowing for rapid and efficient concrete through girder bridge design.

The primary objective is to develop a comprehensive parametric model that allows for systematic evaluation and iterative optimization of design parameters. By integrating python scripting, computational algorithms and external finite elements modelling software, the study aims to provide a parametric design tool that serves as a novel approach the bridge design that yields:
-Flexible tool for structural engineers
-Iterative optimization of structural designs by:
o Minimization of material usage
o Lower environmental impact
o Lower construction costs
-Quicker design process
-Reduction of the cost of change during the design cycle

Key research features include focusing on single-span, single-track train bridges with spans of 25-45 meters and ensuring compliance with Dutch Eurocode and Prorail standards. To achieve this a comprehensive literature review is conducted and a case study of the train bridge spanning the channel is used.
The parametric model also computes an indication of environmental impact and material costs such that generated designs can be evaluated on these criteria.

To evaluate the effectiveness of the parametric model a reference design is considered that fits the scope constraints of the parametric model, namely the through girder bridge at the station of Bilthoven.
To optimize the design of this bridge three redesigns have been generated using the parametric model. The three considered redesigns are:
-Design featuring the same cross-section geometry as the reference design
-Design featuring a 'cut-out' in the centre of the cross-section to save material
-Design featuring an optimized geometry by reducing girder width
For each redesign the pre-stressing and reinforcement layout has been iteratively optimized by getting material usages as close as possible to 100%.

From the three considered redesigns, the optimal redesign manages to reduce material costs by 10.78% and environmental impact costs 11.07%. This is achieved by reducing the thickness of the girder cross-section from 1500 mm as in the reference design to 1200 mm and iteratively optimizing the reinforcement and pre-stressing layout.

The study concludes that the developed parametric model successfully optimizes concrete through girder bridge designs, resulting in significant reductions in material usage and environmental impact for a preliminary design. The model demonstrates the potential for achieving more sustainable and cost-effective bridge designs while meeting all the requirements.
By addressing the combination of structural engineering, computational modelling and sustainability, this thesis contributes to a novel approach of bridge design that can potentially change infrastructure development practices in the Netherlands.

Smartphones have become widely accessible and advanced, pocket-sized computers capable of sensing, sending, and processing an ever-increasing variety of data. Modern phones are, for example, equipped with sensors such as accelerometers and GPS-sensors. Meanwhile, an increase in rail traffic leads to an increase in the need of having a reliable and comfortable railway system, an objective which can be achieved through additional monitoring. Through mobile crowdsensing, the smartphone data from passengers could potentially provide an additional and almost continuous information source on the railway system health state.

This thesis explores to what extent smartphone accelerometer measurements on board of in-service passenger trains can be used to monitor railway track quality. The thesis contains a literature review and a survey with European infrastructure managers. They identify that repeatability, as a result of operational variance, is a key research gap and challenge in the implementation of this technology. The thesis assesses accelerometer characteristics from a set of contemporary smartphones through laboratory tests. The tests uncover limitations and heterogeneity in the sensing capabilities such as sampling frequencies, low-pass filters and eigenfrequencies of the devices. The thesis also makes use of a case study, in which different smartphones are placed in various positions on different in-service passenger trains, running over the same tracks in the Netherlands. The vertical acceleration signals are analysed and compared. The vehicle speed and the position of the smartphone within the car body are found to significantly influence both the frequency content and vertical acceleration amplitudes measured. Finally, the different signals are related back to a Track Quality Index based on the standard deviation of the Longitudinal Level D1 track parameter. A degree of consistency in identifying locations with a low relative track quality is displayed, albeit with a significant degree of variance due to the previously mentioned factors.

This thesis explores the feasibility of drive-by health monitoring (DBHM) for railway bridges using axlebox acceleration (ABA) measurements. Considering the non-stationary nature of train vibrations passing over a bridge, a signal analysis methodology is developed including filtering and time-frequency analysis using the Continuous Wavelet Transform. A vehicle-bridge interaction model combining multi-body dynamics and Euler-Bernoulli beam elements is developed to simulate the influence of local stiffness reduction damage on ABA. Results indicate that both quasi-static and dynamic components of the ABA signal are affected by local stiffness reduction, with the quasi-static influence being more pronounced and localized. A more detailed finite element model simulating a cracked beam is developed to more accurately determine the influence of the local structural damage on the quasi-static component of the ABA signal, revealing that the crack is expected to cause a transient, localized increase in the acceleration. To comprehensively assess the feasibility of DBHM, this research integrates the simulation results with field measurements. To characterize the repeatability of ABA field measurements, measurements from three different measurement campaigns are compared to one another. It is found that the simulated impact of the local damage is overshadowed by the frequency content of the ABA signals in the time-frequency domain, indicating the difficulty to achieve direct damage detection. Alternatively, taking the advantage of DBHM in frequent monitoring, it is concluded with probabilistic analysis that reference signals under healthy conditions combined with multiple passages are essential to confidently identify structural damage. Using a case study of a damaged railway bridge, this paper illustrates both the feasibility and the inherent challenges of implementing DBHM with ABA measurements. As such, this research underscores the need for further field measurements and ABA data analysis for more reliable and accurate structural health monitoring of bridges.

The thesis titled "Towards Smart Maintenance: The Implementation of Predictive Maintenance in the Railway Industry" focuses on integrating predictive maintenance (PdM) technologies into railway operations, emphasizing freight rail. PdM employs data analytics, machine learning, and IoT-enabled sensors to shift from traditional maintenance approaches to a proactive, data-driven methodology. This transformation promises reduced downtime, optimized resource use, and enhanced system reliability.

The research identifies technical, financial, and organizational challenges as key barriers to PdM adoption, including data standardization, algorithm maturity, high initial investment, and resistance to change. Drawing lessons from industries like aviation and infrastructure, the study highlights phased implementation, regulatory frameworks, and stakeholder collaboration as critical enablers.

Employing tools like Interpretive Structural Modeling and Fuzzy MICMAC, the thesis maps interdependencies among barriers and demonstrates PdM's potential for reducing maintenance costs by up to 47.8% over two decades. It concludes with recommendations for systematic adoption, addressing both technical and managerial factors, to ensure safer and more efficient railway maintenance practices.

The comprehensive assessment of the deviatoric behaviour in peats is paramount in ensuring the resilience of soil structures. The understanding of this material is riddled with intricacies, given its highly complex fabric, which includes organic matter such as fibers. This thesis evaluates the capabilities of a recent constitutive model (JMC) to adequately describe the response of peat by means of a flexible combination of constitutive ingredients, such as a non-associate flow rule and mixed volumetric and distortional hardening. The JMC model capabilities are tested with respect to laboratory and field data and compared against well-established models such as the NGI-ADP and Soft Soil (SS) model in a 3D FEM environment. The framework of reference is the measured response of the Bloemendalerpolder test, as it involves long-term consolidation, deviatoric behaviour, and soil-structure interaction. The results of this thesis demonstrate, that although the deformation pattern of the measurements is emulated effectively by the JMC and SS models, all the models show an overestimation of the lateral displacement compared to field data. Despite these limitations of the formulations and the modeling environment, the work shows the potential of the JMC model to reproduce reasonably deviatoric peat behaviour.

In het gebied Apeldoorn – Dieren ligt een oude spoorlijn van de Veluwsche Stoomtrein Maatschappij die op dit moment alleen nog voor toeristisch gebruik wordt geëxploiteerd. Om de bereikbaarheid van het gebied te vergroten wordt er onderzoek gedaan naar de mogelijkheid om hier een railgebonden voertuig op de introduceren. Dit leidt tot de vraag; “Hoe kan in het gebied Apeldoorn – Dieren een railgebonden voertuig worden geïntroduceerd op de oude spoorlijn van de VSM?” Om deze vraag te beantwoorden is er gekeken naar verschillende aspecten. Het gaat hier om de aanwezige infrastructuur, soorten railgebonden voertuigen, relevante referentieprojecten, verschillende technische aspecten, duurzame energietoevoer en aanpassingen die nodig zijn aan de infrastructuur om dit te realiseren. De lijn bestaat uit de stations Apeldoorn, Beekbergen, Loenen, Eerbeek en Dieren. De stoomtrein heeft een eigen dienstregeling en rijdt in het hoogseizoen ongeveer twee keer per dag. De huidige infrastructuur geeft beperkingen voor de introductie van een railgebonden voertuig. Zo ligt er enkelspoor en is de maximale snelheid op de lijn 40 km/h. Voor het railgebonden voertuig is gekozen voor een light rail voertuig. Dit is een licht voertuig wat snel kan accelereren. Verder mag er om de historische waarde van de VSM lijn te behouden, geen bovenleiding worden aangelegd. Om deze reden is er onderzoek gedaan naar verschillende soorten energietoevoer. Vanwege duurzaamheidsredenen en de aanwezige infrastructuur is er gekozen voor een batterij. De energie zal komen van windmolens die in de provincie geplaatst worden. Met behulp van de referentieprojecten zijn er verschillende technische aspecten uitgelicht. Hieruit is voort gekomen dat het van belang is dat de wissels en wielen goed op elkaar afgestemd zijn. Wanneer de wielen te klein of te groot zijn voor de wissels, kan dit zorgen voor ontsporingen, zoals gebeurd is bij de RandstadRail. Verder zijn de perronhoogte, seinen en communicatie tijdens de uitvoering van het project van belang om conflicten te voorkomen. Kijkend naar en rekening houdend met deze aspecten zijn er verschillende aanpassingen nodig aan de lijn om een railgebonden voertuig daarop te introduceren. Dit betreft onder andere de laadinfrastructuur op de perrons van Dieren en Apeldoorn. Verder zijn er ook verscheidene aanpassingen langs de lijn zelf nodig. Denk hierbij aan het verlengen van perrons en het plaatsen van wissels en extra stukken rails. Met behulp van deze aanpassingen is het mogelijk om een voertuig te introduceren wat er 35 minuten over doet om van Apeldoorn naar Dieren rijdt en andersom. Deze zal één keer per ruim half uur rijden. Echter, reflecterend op het onderzoek zijn er verscheidene aannames gemaakt die het niet reëel maken om een railgebonden voertuig op deze lijn te introduceren. Er is al een buslijn aanwezig met dezelfde frequentie die er een kwartiertje langer over doet. Voor de aanpassingen die gemaakt moeten worden aan de infrastructuur weegt dit niet op tegen de gevonden resultaten. Verder is er geen onderzoek gedaan naar de bereikbaarheid en is het niet bekend of de aanname dat deze verhoog moet worden, juist is.

The estimation of railway track parameters from a target frequency response function is a non-convex optimization problem. The objective of this thesis is to evaluate new evolutionary optimization methods to solve the railway track optimization problem. We use a Python based platform, since this programming language is increasing in popularity and new evolutionary algorithms are being made available there. The purpose of the research is to find out which optimizer and objective function performs best. Before the railway track parameters are optimized, tests are conducted on benchmark problems to become familiar with the evolutionary optimization solutions. In this thesis we use Grey Wolf Optimization, Particle Swarm Optimization and Genetic Algorithm. Subsequently, the optimizers are applied on a numerical railway track model from [1]. We focus on the optimization of four parameters, stiffness and damping of both railpad and ballast. Objective function one J1 includes the sum of the differences between estimated frequency response function and target frequency response function in the frequency range 0-12500 Hz. Objective functions two includes the sum of the differences between estimated frequency response function and target frequency response function in the frequency range 0-3418 Hz and gives extra weight to those differences in the frequency range of the track resonances. Objective function three J3 includes the sum of differences of the estimated track resonances and the resonances from the target response. We compare the performance of these optimizers and three different objective functions. We show that it is possible to use all three optimizers to estimate the rail track parameters. We yield the best results with an objective function that only takes the frequency range 0-3418 Hz into account and applies a higher weight factor to differences within the frequency ranges of the track resonances. The compared algorithms behave differently for different objective functions. In most of the tested cases, GWO performed the best. The smallest difference between target parameters and optimized parameters were obtained with objective function two J2. Damping of the railpad is the most difficult parameter to estimate. Stiffness of the ballast was estimated with an error of about 3.90%, stiffness of the railpad with 1,06% and damping of ballast with an error of 3.60%. Finally, part of the further research includes the analysis of other evolutionary computation algorithm, optimization of the whole track model, sensitivity of analysis of the optimization parameters, inclusion of real-life measurements and addressing stochasticities in the objective function.

Transport by rail has taken Europe by storm ever since their introduction in the 19th century. Developments in the past 150 years have led to the construction, deconstruction and reconstruction of various rail connections. In the Netherlands, a small number of lines in its more rural parts no longer have any standard passenger services and are now in use as museum lines, with purposes more focused on tourism and the preservation of history.

This report analyses the possibilities of the reactivation of the Hoorn-Medemblik museum railway line through the use of light rail vehicles. The line is currently only used for a historic tram service as a touristic attraction.

Aspects this report covers are an analysis of the area in which the railway is located and a provisional program of requirements and desires. A legal, infrastructural and traction related framework in which the basic principles and limitations of a revived passenger service are considered. The report specifies and recommends basic operational details on the basis of this.

Rail vehicle valuation is traditionally performed by taking the book value of a vehicle, complemented with a deviation factor for technical characteristics and condition based on the experience of an appraiser. This process is costly and time-consuming for large and/or spread-out fleets and creates financial risks for all parties involved in the transaction through under- or overpricing. To develop more automated and digital approaches to enable more rapid and in-depth economic and financial analysis, insight is needed in the relationship between vehicle value and its determinants. This research aims to identify the main determinants of rolling stock value, and describes – in both economic and statistical terms – the dependence of value on these factors where possible. It reveals that the traditional linear approach to vehicle appraissal does not capture the non-linear effects found between various determinants and vehicle value for both locomotives and freight wagons.

Sustainable railway systems with less disturbance are highly desired. Insulated rail joint (IRJ) is one important structural component in a railway track. IRJs serve the railway system with two crucial functions: dividing track into sections for signal control and enable the detection of broken rails. An IRJ generally consists of two fishplates, insulation layers between the rails and the fishplates, and an end-post layer between two rails. The fishplates are assembled using pre-tensioned bolts. Although the IRJ plays an important role in the railway system, it introduces discontinuities in stiffness and geometry to wheel-rail rolling contact and is thus considered one of the weakest parts of the railway track. Maintenance of IRJs has been an issue of great concern for the rail operators worldwide. Over the past few years many studies have been conducted on monitoring, modelling and analysis of IRJs. Both numerical and experimental studies have been performed in order to gain better understanding of the behaviour of IRJs under static and dynamic loads. Considering that dynamic wheel-rail impacts occur at IRJs, the dynamic behaviour of IRJs should be carefully examined.
This M.Sc. thesis studies the dynamic behaviour of the IRJ experimentally and numerically. Two three-dimensional finite element (FE) track models with different types of IRJ, i.e. a new NRG-joint and normal joint, are developed. Rails, fishplates, insulation layer and sleepers are represented in the models as detailed as possible, while the rail-pads and the ballast are simplified as spring and damper elements. The NRG-joint consists of two fishplates and six pretensioned bolts, while the normal joint consists of two shorter fishplates and four bolts. Implicit FE analyses are first performed to calculate the initial stresses and displacements of the track models, which are then used as initial conditions for the explicit dynamic FE analysis. Field hammer tests are performed on the track line between Zwolle and Meppel. The tests are used on one hand to calibrate the stiffness and damping parameters involved in the rail-pad and ballast models, and on the other hand to validate the dynamic behaviour reproduced by the FE IRJ models. The comparison between the simulation and the measurements shows reasonable agreement of the results. Based on the validated FE models, optimisation strategies of the dynamic behaviour of the IRJ are proposed by a parametric study. The varied parameters include stiffness and damping of the rail-pads and the ballast as well as sleeper span. Implementation of non-uniform sleeper span seems effective for reducing pinned-pinned resonance. Finally, conclusions are drawn and recommendations for further research are made.

This Bachelor’s thesis presents a comprehensive study of the static wheel/rail contact problem using Finite Element Analysis (FEA) with a parametric modeling approach. The work begins with a historical overview of the wheel/rail contact problem, highlighting the critical phenomena that occur at the wheel-rail interface. The thesis then delves into the Hertzian contact theory, providing a theoretical foundation for the subsequent modeling of the wheel-rail contact problem using FEA. A detailed description of the Finite Element Model (FEM) macro is provided, explaining the process of modeling the wheel/rail contact problem. The study concludes that FEA is a powerful tool for analyzing the wheel/rail contact problem, and the parametric modeling approach offers adaptability for future improvements and easy adjustments. The thesis underscores the importance of validation against analytical solutions to ensure the accuracy of the FEM model. As a future direction, the thesis recommends further research to apply different loads, explore relative positions of wheel and rail, and investigate different contact elements for modeling real-world contact behavior. This work serves as a stepping stone towards future research and a more comprehensive understanding of the wheel/rail contact problem.